Minutes of
the 2006 NCERA-148 Annual Meeting
Chairman
Rob Venette opened the meeting at
The
following individuals attended the meeting: Annalisa Ariatti, David Byrne,
Manuel Colunga-Garcia, Joe Dauer, Erick DeWolf, Nick Dufault, Howard
Fescemeyer, Shelby Fleischer, Regula Gehrig, Julie Golod, Rick Hellmich, David
Hogg (Administrative Advisor), Casey Hoy, Bill Hutchison, Scott Isard, Tim
Leslie, Rick Meyer (USDA-CSREES), Dave Mortensen, Forrest Nutter, Megan
O’Rourke, Matt Royer, Joe Russo, Tom Sappington, Elson Shields, Joe Spencer,
Elwynn Taylor, Rob Venette, John Westbrook, Jeremy Zivek.
Minutes
of the 2005 meeting were unanimously approved.
Membership
Committee (Scott Isard)
- Goal is to invite
graduate students; expose them to NCERA-148; and encourage their membership.
- Manuel
Colunga-Garcia and Roger Magarey have become NCERA-148 members in 2006.
Website
Committee (Rob Venette)
- NIMSS Web page has
been maintained; Rick Hellmich was commended for uploading the 2005 Impact
Statements onto NIMSS Web site.
- Uncertain future of
NCR-148 Web site
- Plan to move
content from (and close link to) previous NCR-148 Web site.
- Scott Isard
suggested hosting NCERA-148 Web site at
Awards
Committee (Casey Hoy)
- Recommended identifying
previous award recipients and maintaining a list of previous award
recipients on the NIMSS Web site.
- 2006 Award
presented to David Byrne for significant contributions to NCR-148 since
1984.
Impact
Writing Committee (Rick Hellmich)
- Need to request
submission of Impact Statements at annual meetings.
- Secretary rotates
onto Impact Writing Committee every year.
Nomination
Committee (Tom Sappington)
- Tom Sappington and
John Westbrook nominated Shelby Fleischer as the candidate for
secretary/treasurer, who was elected by a unanimous vote.
Site
Committee (Elson Shields)
- Scott Isard and
Elson Shields recommended
CSREES
Report (Richard Meyer)
- Distributed copies
of the 2005 NCERA-148 Impact Statement report, which had been prepared by
Amy Rhodes, CSREES; Amy has vacated her position, which will likely be
refilled.
- Referred to the CSREES
web site (IPM section)
- CSREES budget is
flat for FY2007.
- Request for USDA
competitive grant proposals will be posted within a few weeks.
- Distributed copies
of the CSREES Plant Sciences Update.
- Discussed phase-out
of Congressionally-earmarked grants (sunset report).
- Reported appointment
of new CSREES National Program Leader for Plant Pathology, Marty Draper, will
assume responsibility of Pest Management Centers.
- Secretary of USDA Award
– Prestigious commendations to Scott Isard and Julie Golod for important multi-Agency
work on Soybean Rust.
Administrative
Advisor Report (David Hogg)
- Described state of
turmoil regarding Hatch Funds (formula funds)
- Hatch funds have
been restored and slightly increased in FY2007.
- OMB wants all
future government research funds to be competitively awarded.
- Create 21 – “How to
fund agricultural extension and research (capacity).”
- NIFA -- May be
enacted along the lines of NIH funding.
- David Hogg will move
from administration back into academia.
- David Hogg will be
replaced as Administrative Advisor and encouraged recommendations for his
replacement:
- Elson Taylor
recommended Wendy Winterstein (
- David Hogg
recommended Sonny Ramaswamy (
- Casey Hoy
recommended Bill Rathman (
- Forest Nutter recommended
Ray Hammerschmidt (
David
Byrne recommended sending a letter of thanks to Joe Russo, owner of ZedX, for
use of conference room facilities; Rob Venette affirmed that he would send the
letter.
State
Reports (Secretary John Westbrook requested State Reports within 3 weeks after
the meeting). Bullet statements
summarizing the State Reports are listed below; extensive State Reports are
provided separately.
- Parasitoid life
history and flight fuels for their dispersal
- Whitefly
parasitoid fauna (5 species)
- Investigated
western corn rootworm (WCR) movement from refuges into transgenic corn.
- Used Cry proteins
from transgenic corn as marker of WCR beetles (detectable up to 24 hours).
- Research results
suggested use of strip-planted refuge.
- Manipulated
spatial distribution of adult European corn borers (ECB) using mosaic of
plantings of host plants.
- Released
susceptible marked moths into landscape.
- A tether saddle was
attached with superglue to abdomen of adult ECB for use on flight mill.
- Suggested use of
cold temperature to cause moths to be still during tethering.
- Discovered that Nosema pathogen reduced flight
capability of adult ECB.
- Population
genetics of Bt-corn IRM monitoring of ECB
- Developed and used
microsatellites for discrimination of ECB.
- Discussed research
on plot size for evaluating movement of adult ECB.
- Will host Chinese
scientist to share research techniques and results for marked-study of corn
borers.
- Discussed research
on human-mediated pathways of invasive species.
- Metropolitan areas
- Integrated
databases of foreign imports and ports of entry to determine risk
assessments of vulnerable metropolitan areas (including built-up and
non-built-up areas).
- Distributed State
Report from Rufus Isaacs
- Discussed remote
sensing, GIS, GPS technologies for plant disease epidemics (Asian soybean
rust).
- Explained that diagnostic
analysis of near-infrared intensity gradient within field:
- Can’t
differentiate spectral characteristics of various pathogenic spp.
infections;
- Can distinguish
spatial characteristics within field; and
- Can identify foci
of infection by calculating centroid.
- Discussed long-term
risk assessment of Asian soybean rust infection based on wind
trajectories (lower and upper trajectories).
- Discussed several
Web-based corn earworm data bases and models:
- ZeaMap (www.vegedge.umn.edu);
- Insecticide
Resistance Monitoring (pyrethroids);
- PestWatch (www.pestwatch.psu.edu);
and
- Insect Migration
risk assessment (www.maplecity.com)
- Discussed major
research program using a fleet of large radio-controlled airplanes to
collect airborne biota.
- Discovered migratory
flight response of potato leafhopper to barometric pressure changes.
- Each aircraft
costs about $5K to $10K.
- Discussed several
research projects:
- Ash firewood from
- Robin Taylor has
used insect flight mills.
- Remote sensing of
infected ash.
- Diamondback moth
response to permethium residue and susceptibility.
- Entomopathogenic
nematodes and soil management to enhance nematode populations around
perimeter of cropland.
- Distributed
copies of the Proceedings of the National Academy of Sciences paper by
Alison Snow et al.
- Announced advertised
research positions at the Ohio Agricultural Research and
- Announced that he
will move into a new position and no longer participate in NCERA-148.
- Soybean Rust
- Summarized research
on biophysical factors and dispersal modeling, including ensemble
aerobiological models.
- PIPE (
- Described IPM
decision support system
- Announced formation
of a PIPE Steering Committee.
- Interested in
reviewing previous Areawide Heliothis
project organized by John Goodenough (1983-1986).
- Discussed
migratory Lepidopteran map output.
- Described
collaboration with Howard Fescemeyer on microsatellite genetic analyses.
- Discussed physiological
and molecular basis of flight capability in moths and butterflies.
- Discussed research
on dispersal of Round-Up-resistant weed seeds.
- Summarized
research on spring dispersal of adult cotton fleahoppers from weeds.
- Provided update on
NSF-ITR project about bat foraging on crop insect pests.
Joe
Russo (ZedX) “Useful resources for movement and dispersal studies”
- ZedX is an IT
company (weather data is one major element with and agricultural emphasis)
- Physical systems
protections
- Facility layout enhances
interaction among scientists
- Open-source
approach to data/systems programming
- Redundant
teleconnections
- CPU/utility backup
capability
- Weather data quality
control
- Dependent on
forecasts, data collection
- Helps to
understand limitation (uncertainty) of weather data
- Prepares data
format and product output
- Reliable products
and service availability
- Maintains customer
base
- Fully automated
service
- Private data
services
- e.g., farmer
applications
- Customer model building
with access to database
- APHIS
- NAPPFAST
- Focal point: It’s
about people using IT technology
- Data management
moves individual databases of various structures into SQL databases (Cyber
infrastructure)
- Weather data
sources
- Degrading quality attributed
to automated stations
- WRF Mesoscale Model
(12-15 km gridded)
- Global model
forecasts to be available in 2007
Matt
Royer (USDA-APHIS) delivered the presentation titled “Regulatory agency with
methods development responsibility”
- Homeland Security
presidential initiative
- Communication and
response to agricultural security
- IT pest detection
modeling (PIPE models)
- NAPIS reports at
county level and cannot report at the individual property level
- Need to prioritize
pest surveys and risk assessments
- APHIS needs to
involve industry earlier to determine scope of risk management goals
- EXCERPT (Export
Certification)
Rob
Venette (Forest Service) delivered the presentation titled “Needs for dispersal
research in a charter for exotic invasive species research and development”
- Setting 10-year
plan on invasive species (insects, pathogens, weeds)
- Need to prioritize
to allocate limited resources
- Need to work as a “coalition
of the willing”
- Look for common
arrival, establishment, integration, and spread among the invasive species
- Invasive species
management plan
- Focus on global
scale
- See Venette and
Cohen (2006) paper in Forest Ecology and Management about climate
suitability for P. ramorum
Megan
O’Rourke (
- Do treelines slow
ECB dispersal?
- Examined first-year
non-Bt corn fields for ECB, western and northern corn rootworms, and pink-spotted
lady beetles
- WCR population
were significantly higher in high corn density counties
- Lady beetle
populations were significantly lower in high corn density counties
- Will add sampling
of corn leaf aphids in 2007.
- Can these results
be used to infer scales of dispersal?
Nick
Dufault (
- Asian soybean rust
- Wet and dry
deposition
- Effect of
environmental and production practices on infections
- Rainfall simulator
with incorporated spores for wet deposition
- Rainfall
distributes spores evenly within canopy, but can also wash off spores
from upper canopy
- Dry deposition
experiment using fluorescent particles
Joe
Dauer (
- Round-up resistant
horseweed (a.k.a. marestail or Canadian fleabane)
- Horseweed seeds
with pappus (similar to parachute)
- Vertical screen
traps on towers and radio-controlled aircraft net sampling of airborne
seeds
Final
Business
- Next meeting –
Meeting
adjourned at
State
reports
2006 State Report for
NCERA-148
Thomas W. Sappington,
USDA-ARS,
Effects of gender, age, mating status, and Nosema
infection on laboratory flight behavior of European corn borer moths.
Thomas W. Sappington,1,2 David L. Dorhout,2 Marlin
E. Rice,2 and Leslie C. Lewis1,2
1USDA-ARS, Corn Insects & Crop Genetics Research
Unit,
2Dept. of Entomology,
European corn borer (ECB) (Ostrinia
nubilalis) is a major pest of corn in
In the first study, we used computer-interfaced flight mills to compare
flight behavior of moths of different age, sex, and mating status. Moths used in this study were reared at the
USDA-ARS Corn Insects laboratory in
Data analyses are ongoing, but preliminary analyses of the parameter
“distance of longest single flight” are consistent with an obligatory dispersal
phase for unmated females (6.2 + 1.0 km at 1 d old, decreasing to 3.5 +
0.7 km at 5 d old). The pattern for
males (1.7 + 0.4 km at 1 d old, increasing
to 4.2 + 0.9 km at 5 d old) was quite different than that of females,
but the distance flown on the first night after emergence was nevertheless
substantial. It was not possible to test
the flight behavior of 1 d old mated moths, because they would have to have
been flown the same night of mating. The
distance of the longest flight of 2 d old mated females (3.0 + 0.7 km)
was about half that of unmated 1 d old females, but not significantly different
than that of unmated 2 d old females (5.0 + 1.0 km). The distance of the longest flight of 2 d old
mated males (1.8 + 0.5 km) was very similar to that of unmated 1 d old
males, and not significantly different than that of unmated 2 d old males (2.8 +
0.8 km).
In a second set of experiments, we examined the effects of infection by Nosema pyrausta, a common protozoan
pathogen in the US Corn Belt, on laboratory flight behavior of unmated 1 d old
males and female ECB. We did not have
enough material to compare other ages or the effects of mating. The moths were taken from a separate colony
maintained at the Corn Insects Laboratory.
Both nominally infected and uninfected moths were weighed and dissected
after flight, and the level of infection was determined as spores/mg body
weight. Wings were removed from the
moths after flight and scanned to facilitate measurement of wing length and
area.
Preliminary analyses indicate that Nosema-infected
adults of both sexes are much smaller than their uninfected counterparts, the
former weighing only 50-60% of the latter.
Observations of wing scans indicate that this difference is reflected by
substantial differences in wing size, though quantification of wing
measurements is ongoing. The median
distance of the longest flight of infected females (0.76 km) and males (0.21
km) was much less than that of uninfected females (3.3 km) and males (1.4 km)
from the same colony. Plotting distance
of the longest flight against level of Nosema
infection suggests that there is a threshold effect, such that flight is not
affected in females until infection levels are greater than about 30 spores/mg
body weight. Likewise, flight of males
is not affected until infection levels are greater than about 50 spores/mg body
weight. This threshold effect suggests
that differences in flight behavior in Nosema-infected
and uninfected moths are not caused by differences in body weight or wing size
per se. Rather, moths infected at a
level above threshold likely have insufficient energy reserves in the fat body
to fuel prolonged flight activity.
Impact Statement:
Evidence from a series of mark-release and
laboratory flight mill studies suggest that European corn borer undergo an
obligatory dispersal flight away from the natal field the first night after
emergence from the pupa. Distance of
this flight is variable, but may average several km. These findings will substantially affect
predictions of Bt resistance development and rate of spread through
populations, because the working assumption has been that ECB reside and mate
near their natal field.
Recent Publications Relevant to NCERA-148:
Reardon, B. J., D. V. Sumerford, and T. W. Sappington. 2006.
Impact of trap design, windbreaks, and weather on captures of European
corn borer (Lepidoptera: Crambidae) in pheromone-baited traps. Environ.
Entomol. (In press)
Reardon, B. J., D. V. Sumerford, and T. W. Sappington. 2006.
Dispersal of newly-eclosed European corn borer moths (Lepidoptera:
Crambidae) from corn into small-grain aggregation plots. J.
Econ. Entomol. 99: 1641-1650.
Kim, K. S., P. Cano-Ríos, and T. W. Sappington. 2006. Forum: Using genetic markers and
population assignment techniques to infer origin of boll weevils (Coleoptera:
Curculionidae) unexpectedly captured near an eradication zone in
Kim, K. S., and T. W. Sappington.
2006. Molecular genetic variation of boll weevil populations in
Sappington, T. W., M. D. Arnold,
A. D. Brashears, M. N. Parajulee, S. C. Carroll, A. E. Knutson, and J. W.
Norman Jr. 2006. Dispersal of boll weevils (Coleoptera:
Curculionidae) from cotton modules before ginning. J.
Econ. Entomol. 99: 67-75.
Sappington, T. W. 2005. First-flight adult European corn borer
(Lepidoptera: Crambidae) distribution in roadside vegetation relative to
cropping patterns and corn phenology. Environ. Entomol. 34: 1541-1548.
2006 State Report for
NCERA-148
Joseph L. Spencer,
NCERA-148:
Migration and Dispersal of Insects and Other Biota
Synopsis of Activities in 2005-2006
Joseph L. Spencer, NCR-148 State
Representative
Section for Ecological Entomology,
Participants in Movement and Dispersal Research. Joseph L. Spencer (INHS), Eli Levine (INHS), David Onstad (NRES), and
Dave Voegtlin (INHS).
Cooperators. Mike Gray (Crop Sciences) and Kevin Steffey (Crop
Sciences).
Highlights of Movement and Dispersal Activities at
·
Extramural corn rootworm movement-related grant
proposals were funded by:
o
USDA-NRI (“Trap then manage: using corn rootworm
behavior to reduce producer inputs and optimize resistance management for
transgenic corn.” J. Spencer, K.L.
Steffey, and M.E. Gray)
o
USDA-RIPM (“Movement of
rotation-resistant western corn rootworm beetles from soybean fields to
cornfields.” J. Spencer, D. Onstad,
and E. Levine).
·
Interfield WCR movement and mating studies related
to transgenic corn refuge designs (supported by Monsanto) suggest mating
activity in transgenic corn is not the same as that in adjacent non-transgenic
refuges.
·
A state and region-wide suction trap network was
operational in 2006, providing data on soybean aphid captures from across
Relevant Publications (2005-2006).
· Knolhoff,
L., D. Onstad, J. Spencer, and E. Levine. 2006. Behavioral differences between
rotation-resistant and wild-type
Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Environmental Entomology.
35(4):1049-1057.
· Spencer,
J.L. 2006. Tracking movement of
mate-seeking WCR males between refuges and transgenic corn. INHS Reports, Summer 2006, No. 388, p.1.
· Crowder,
D. W., D.W.
· Levine,
E., J.L. Spencer, T.R. Mabry, and
·
Spencer, J.L., T.R. Mabry, E. Levine, and
·
Spencer, J.L., S.A. Isard, and E. Levine.
2005. Movement of western corn rootworm
adults within and between fields: implications for resistance management, p.
28-34. In Proceedings of the
APPENDIX I:
RESEARCH REPORTS
Rotation-Resistant Western Corn Rootworm Movement
Studies. Principal Investigators: Joseph Spencer & Eli Levine, Section of
Ecological Entomology,
1). Movement of rotation-resistant western corn rootworm
beetles from soybean fields to cornfields. Interfield movement studies of
rotation-resistant WCR adults have previously focused on beetle travel from
corn into rotated crops. In 2006, we
began a study looking at WCR movement from soybean into cornfields. The presence
of abundant WCR adults in soybean (or other rotated crops) is diagnostic of
rotation-resistant WCR populations. Those WCR that enter soybean fields to feed
and/or lay eggs must return to cornfields to locate food resources that will
permit maturation of eggs; soybean tissues, though readily consumed, do not
provide significant nutrition to WCR adults.
It was hypothesized that detection of ingested soybean tissue inside WCR
adults captured at the edges of cornfields could be used to measure local levels
of rotation-resistant WCR activity in an area. If successful, this method might
be useful to rapidly determine if rotation-resistant WCR were active in a
particular field. Availability of
EnviroLogix QuickStix detection devices specific for the CP4 EPSPS protein
expressed in Roundup Ready soybean (‘RR-soybean’) allowed us to detect ingested
Roundup Ready soybean tissue in WCR adults. This ability made it possible to measure the
proportion of individual cornfield WCR that had recently returned to cornfields
following feeding activity in soybean fields.
The WCR adults from soybean fields into adjacent cornfields was measured
in six pairs of commercial RR-soybean fields non-RR cornfields and as well as
in three 4-acre research plots divided into 2-acre subplots of RR-soybean and
non-RR corn. WCR adults were collected
at the interface between the crops. In
soybean, sweep samples were collected in rows 1, 5, 10, and 15; in corn WCR
were collected from rows 1, 5, and 10.
To study periodicity in interfield movement, on seven days, collections
were repeated during four time intervals:
Impact
Statement: An assay that could measure the level of rotation-resistant WCR
activity in specific fields within a few minutes, would encourage greater
monitoring for rotation-resistance.
Current monitoring protocols using Pherocon AM traps are rarely used,
resulting in unnecessary use of soil insecticide or rootworm transgenic corn on
the 10-20% of rotated corn in the northern half of
2). Intra-field
movement and mating of male WCR between refuge and YieldGard® Rootworm
transgenic corn. Transgenic corn tissue detection methods were used to
monitor the movement and mating activity of WCR beetles dispersing from a 20%
structured refuge cornfield with two areas (15-rows and 75-rows) of Monsanto’s
YieldGard® Rootworm (the transgenic, comprising 80% of
the field area) on either side of a 24-row strip of Monsanto’s YieldGard®
Cornborer hybrid (because this hybrid does not affect WCR larval development it
serves as the non-WCR transgenic hybrid and was the refuge). The Cry1Ab protein
expressed in the YieldGard® Cornborer served as a marker to allow movement from
the refuge into the Cry3Bb1 transgenic to be reckoned. Detection of Cry1Ab
protein in mating WCR pairs in the transgenic area of each field (n=4, 2-acre
plots) allowed intrafield movement of males and females to be measured directly
and allowed a direct measurement of refuge ‘function’ to be assessed. In 2005, mean male WCR movement rates (ca.
6.1 m/day) did not differ between males captured while mating and those taken
while moving about singly (mated pair QuickStix processing is not complete for
2006 insects). In both ’05 and ’06, Male
movement rates were highest before female emergence peaked, thereafter males
did not move as fast. Also, in both
years, the female member of a mating WCR pair was 10 times more likely to be
newly emerged (i.e., still teneral) when collected in a refuge than when
collected in the rootworm transgenic areas of a field. These data suggest that the more scarce
calling females that emerge from rootworm transgenic corn may not be found my
mate-seeking males as rapidly as females emerging in the refuge. If confirmed, delayed mating of females in
transgenic corn may indicate that key assumptions about male movement/mating or
female mating may be wrong under refuge conditions commonly accepted as part of
IRM plans for corn rootworms.
Impact Statement: Detection of un-met behavioral expectations for mate-seeking WCR in
transgenic corn suggests that current refuge configurations for rootworm
transgenic corn may need to be re-visited; these data will be useful to that
re-evaluation. WCR resistance to Bt transgenic corn would force many
Soybean Aphid Monitoring. Principal Investigator: Dave
Abundant soybean aphids in Fall 2006, potential
problems for Summer 2007? The number of soybean aphids caught during July and August 2006 was
considerably lower than seen in 2005 with no trap exceeding 200/week. Highest counts were in
Similar to some of the previous years, a summer of
low trap catches and corresponding low field populations has been followed by a
large fall flight. Unfortunately, we do
not have regional numbers for the fall flight in 2002 and 2004 that were each
followed by an outbreak season so it is only possible to compare using the
2001 –
24
2002 –
732
2003 –
22
2004 – 1,765
2005 –
269
2006 –
1,420 (incomplete)
Fall counts for the
Impact Statement: Annual soybean aphid abundance monitoring has revealed
a 2-year cycle of high and low Fall populations of aphid migrants. Knowing that an abundant fall flight of
migrant aphids is associated with an increased likelihood economic injury in
soybean during the following year allows growers to anticipate a need to take
action.
Large numbers of winged (alate) soybean aphids on buckthorn leaves,
2006 State Report for
NCERA-148
Andrei Alyokhin,
Diurnal
Patterns in Host Finding by Potato Aphids, Macrosiphum
euphorbiae (Homoptera: Aphididae)
Andrei Alyokhin
Department of Biological Sciences,
Potato aphid, Macrosiphum
euphorbiae (Thomas), is the most abundant species colonizing potato plants
in
Short-distance
movement of viruliferous aphids may be responsible both for enlarging existing
disease foci, as well as for creating new foci within the same field. Because of their high mobility, winged aphids
are generally considered to be more important in spreading viruses between plants
than wingless aphids. However, there is evidence that dispersal of wingless
aphids can also result in infection of a substantial number of plants. Earlier
study (including ours) showed that wingless potato aphid was the most mobile
potato-colonizing species. Therefore, its movement between plants may be a
significant factor in viral outbreaks in potato fields.
A considerable
amount of research effort went into studying the regulation of aphid physiology
(particularly in relation to its life cycle) by changing photoperiod,
temperature and humidity. However,
relatively little is still known about aphid activity patterns during a 24-hour
daily cycle. We investigated the circadian rhythmicity of movement of wingless
adult potato aphids towards host plant odor.
Effects of
daily cycle (day or night) and illumination (light or dark) on the proportion
of aphids colonizing potato leaflets were determined in a Petri plate arena and
in a Y-tube olfactometer. In Petri
dishes, both daily cycle and light had a highly significant effect on plant
colonization (Fig. 1). Increasing
temperature reduced aphid colonization of the leaflets. In the olfactometer, light had a significant
effect on the proportion of aphids walking towards the host plant. Interaction between time and light was also
statistically significant, with the effect of illumination being smaller during
the day than during the night (Fig. 2).
The trend
towards stronger aphid response during the photophase persisted even in
complete darkness. This suggests
endogenous regulation of the observed behavior.
At the same time, illumination greatly increased aphid movement towards
host plants, effectively overriding effects of daily cycle during the
scotophase. Therefore, it appears that
aphid movement towards host plants is affected by both endogenous and exogenous
regulation mechanisms.
Impact Statement: Better understanding of the
diurnal rhythms of wingless potato aphids in their host finding activity can
potentially improve (1) existing insect monitoring programs/ IPM scouting, (2)
planning and scheduling the most efficient time for pesticide sprays, and (3)
evaluation of new biological control agents by matching activity patterns of
natural enemies and their target pests.
Publications:
Narayandas, G. and A. Alyokhin.
2006. Diurnal patterns in host finding
by potato aphids, Macrosiphum euphorbiae
(Homoptera: Aphididae). Journal of Insect Behavior 19: 347-356.
Fig. 1. Colonization of excised potato leaflets by
adult potato aphids under the light and dark conditions during day and night in
Petri-dish arenas. Error bars indicate
standard errors.
.
Fig. 2. Colonization of excised potato leaflets by adult potato aphids under the
light and dark conditions during day and night in an olfactometer. Error bars indicate standard errors.
2006 State Report for
NCERA-148
Quantifying local dispersal of Japanese
beetle
Rufus Isaacs & Steve Van Timmeren
This project aims to
determine the dispersal capabilities of adult Japanese beetles, Popillia japonica, within fruit crop
landscapes. Mark-release-recapture and release-recapture experiments have been
conducted to better understand the movement of this damaging pest insect. Our
long-term aim is to use the data in spatially-explicit modeling of the dynamics
of this insect across agricultural landscapes, to assist with the design of
agricultural systems that are suppressive to this insect. This information
should be valuable for agricultural regions near infested regions that may then
be better able to resist invasion and establishment of this pest as it continues
to expand its geographic range.
1. Release of beetles at varying distances from monitoring trap. Three separate releases of
Japanese beetles were conducted at the Trevor Nichols Research Complex in
Beetles were released in
sand-filled trays at 10, 50, 100, 200, and 400 meters east of a set of six
pheromone traps placed within 5 m of each other. Releases took place around
1000 h on each of the release dates (September 1, 8, and 14). The landscape along the transect was
primarily open field with some fruit trees (primarily apple, pear, and peach)
and
The overall level of recapture in this trial was 11.1% of beetles
released. Similar numbers of male and female beetles were recaptured of those
released 10 m away from the traps (Fig. 1). However, at all longer distances,
more females were caught, suggesting greater dispersal capacity in female
beetles.
Seventy four percent of beetles recaptured were collected within the
first six hours (Fig. 2), with a small increase at the start of the second day
of the trials (92% of recaptures), data not shown. This suggests that female beetles
are capable of rapid movement of their eggs to distant oviposition sites. Our
findings have important implications for the local spread of this species by
flight, since females will be able to fly and locate suitable oviposition sites
within a large area over a short time period. This suggests that unless
controlled quickly after emergence from the ground and the subsequent mating,
egglaying will occur and larvae will be established in suitable sites for
development and emergence for the subsequent growing season.
2. Large-scale recapture of
beetles across a fruit crop landscape. Five thousand adult beetles were released from a
central release site at the Trevor Nichols Research Complex in Fennville
Beetles were collected from another infested site and released at this
research station prior to the emergence of the local Japanese beetle
population, avoiding potential complications of a background population and
allowing release of unmarked beetles. Beetles were fed overnight on sassafrass
leaves in 12 x 24 x 8 inch containers with 500 beetles per container. Beetles
were transported to the release site at 0800 h and released at 1000 h. Traps
were checked up to four days after the release, although 80% of beetles were
recaptured during the first day. Only seven beetles were recaptured in the
traps placed beyond 1 km from the release site, and so our regression analysis
was conducted on the captures within the fruit farm (< 1 km). For these
traps, there was a significant negative relationship between distance from the
release point and number of beetles recaptured (Figure 3), with distance
explaining 50.4% of the variation in beetle captures (F1,25 = 25.4,
P<0.0001).
The directionality of
the beetle’s dispersal was also determined, by analyzing the frequency of
recaptures of beetles in the traps relative to their angular direction from the
point of release (North = 0 degrees). Oriana software (KCS Inc.) was used to
conduct circular statistical analyses. The mean angle of beetle recapture was
255.4 ± 26.0 degrees (WSW). However, there was a relatively uniform
distribution of the recaptures (Figure 4) as determined by Rayleigh’s test
(Z=2.41, P=0.089). This suggests that the dispersal of beetles across a
landscape is not highly biased in any particular direction.
Future directions. We are currently analyzing
samples from additional releases of Japanese beetles that were marked with an
immunoglobulin (IGg) marker, to determine the suitability of that marking
system for mass marking of beetles prior to release. Additional research has
measured the local dispersal of Japanese beetles in three crop landscape types
(soybean, blueberry, and fallow field), and we will be comparing the movement
and spatial distribution of beetles within these three field types. As
mentioned above, results from these studies will be used to incorporate
movement parameters into a spatially-explicit model of Japanese beetle movement
within agricultural landscapes.
Impacts. Quantification of the local dispersal capabilities
of Japanese beetle will help determine the appropriate spatial scale that
management activities must be adopted on farms when attempting to disrupt the
establishment of this pest.
For more information,
contact Rufus Isaacs, 202 CIPS,
2006 State Report for
NCERA-148
Elson Shields,
Role of aerial
sampling of biota
Collecting aerial biota aloft in the
upper surface boundary layer and the planetary boundary layer is needed to
transition theoretical hypothesizes to a data driven thought process. Full scale aircraft and helicopters have been
used in the past to make these collections but their usage is expensive and the
limitations of a minimum altitude of 500 ft and operation during non-turbulent
atmospheric conditions had limited their usage in aerobiology. The use of smaller unmanned remote piloted
vehicles (RPVs) has opened the opportunity for more extensive aerial sampling,
including the lower 500 ft of the atmosphere and during turbulent conditions
associated with the close proximity of a storm front. These RPVs are less expensive to purchase and
operate, are allowed to operate from
ground level up in the atmosphere and no human life is at risk during operation
in the turbulent conditions associated with storm front passage.
Aerial Densities of
biota:
Before attempting the aerial
collection of biota, the aerial density of the target biota is an important
piece of data so the capacity of the aerial collection device can be matched to
the target biota. A search of the
literature including recent research articles indicate that the aerial density
of micro-organisms and pollen fall into the range of 0-50 particles per m3
of air sampled. Weed seeds such as
Horseweed, Conyza canadensis, and
insects such as aphids and leafhoppers have aerial densities of 0-50
individuals per 1000 m3 of air sampled. This information indicates there are 3 orders
of magnitude between the densities of these two groups of aerial biota.
A remote piloted vehicle system
(RPV) has been developed and utilized in various projects over the past 10
years which has the capability of sampling 6-10 m3 of air per min (6,000-10,000 L of air per min)
per sampler. The RPV carries 4 samplers
aloft which can be opened individually.
Each RPV is equipped with an on-board data logger, GPS antenna and
telemetry down link. On board fuel load
allows the RPV to fly at full throttle for a 30-min sample with fuel reserve
for takeoff and landing. Total air
sampling capacity with all samplers open for 30 min equals 1200 m3 of
air.
Impact of the RPV
system on selected research projects:
Wheat Fusarium Head
Blight (conclusions after ca. 250 sampling flights)
(Bergstrom, Maldonado, Schmale,
Shields)
1) Live spores are in the planetary boundary layer 24/7 for the entire
growing season.
2) Aerial populations are very genetically diverse regardless of time of
day or time of year.
3) Viable spores can be collected a distance away from any current source
at any hour of the day.
4) Wheat heads and corn ears are infected from gravitational settling of
aerial spores after dark.
5) Due to low settling velocities, spores only settle out of the lower
200-300 ft of the atmosphere during the night-time hours.
6) Suggesting that the source of an epidemic may originate many miles away
(rather than local splash).
7) Refocusing the national discussion on sources, long-ranged movement and
management for this disease.
Long-range Movement of Corn Pollen (conclusions after ca. 350 sampling
flights over 4 years) (Aylor, Boehm, Shields)
1)
Corn pollen survival > 3 hrs in the atmosphere.
2)
Aerial density over a field = 1-10 pollen grains /
m3 of air.
3)
Corn pollen collected as high as 1000 ft above
ground level (highest level sampled).
4)
Corn pollen has the potential to be moved miles.
5)
Corn with traits which need isolation should not be
grown in areas with other corn present.
Long-range Movement
of Roundup-resistant Horseweed (conclusions after ca. 66 flight over 2 years)
(Dauer, VanGessel, Shields, Mortensen).
1)
Seeds are released from
2)
Most seeds are lifted aloft from noon-3 pm.
3)
Viable seeds have been collected 450 ft above
ground level, well into the Planetary Boundary layer.
4)
Aerial density of seeds is 0-9 seeds per 1000 m3
of air sampled.
5)
Seed movement under light wind = 50-90 miles and
300-375 miles with a 40 mph wind.
6)
Gene flow between populations has a new broader
focus.
Migration of Potato
Leafhopper (Shields)
A larger RPV system has been
developed to be used in the study of Potato leafhopper migration. These RPVs sample 1000-1300 m3 of
air per min depending on whether the RPV is powered by a 16 hp or 20 hp
engine. In addition, the RPVs are
equipped with high intensity LEDs for operation during dusk and full darkness
which coincides with leafhopper takeoff activity. This fleet of RPVs will be used to explore
the change of migration behavior observed in potato leafhopper between the
northward spring migration and the southward fall migration. Research will be conducted during the 2007
growing season.
2006 State Report for
NCERA-148
Casey W. Hoy,
New Positions Related to Research on Migration and
Dispersal Anticipated in the Department of Entomology, OARDC
The following position has been approved and the search
committee has been formed:
Insect Population Geneticist/Agronomic Crops
We are seeking a broadly trained Population Geneticist with
excellent molecular and quantitative skills, to address population genetics or
genomics with concentration in management of insect pests of agronomic crops.
Research could focus on gene flow among insect populations, resistance
management, metapopulation dynamics of above or below ground insects, invasive species
or other questions of importance to state, national and international
interests. (see attached position announcement) Two additional positions are
anticipated in the near future, and the following are draft descriptions:
Applied Landscape Ecology/Horticultural Food Crops
Insect pests tend to be mobile, to occur over large areas,
and to be affected by the changes in land use and land management that occur
across the landscape. These pest characteristics are particularly acute in
horticultural food crops, in which the most intractable problems are caused by
highly mobile insect pests and plant disease vectors, but can occur for any of
the other commodities requiring protection from insect pests. Over the past 25
years, landscape ecology has emerged as a branch of ecology that focuses on
spatial variation in landscapes at a variety of scales and its impact on
ecological processes, including insect pest dynamics. The field has focused on
both the biophysical and societal causes and consequences of landscape heterogeneity,
and therefore fits the multidimensional reality of integrated pest management. Opportunities
in this field have blossomed in the past decade, as computing software and hardware
has become available to document, measure, and analyze spatial patterns of
plant and animal populations and key aspects of their physical environment at
broad spatial scales. This proposed position would fouc on opportunities for
managing spatial heterogeneity in agricultural landscapes in order to improve
pest management, with special emphasis on horticultural food crops. Examples of
research conducted in this program might include but not be limited to:
• the influence of crop and non-crop diversity and pattern
on success of biological control,
• regional approaches to deployment of resistant host
plants,
• pest management decision-making at whole-farm or regional
scales,
• spread and containment of exotic pest invasion into
• area-wide management of highly mobile and migratory pests,
• pest phenology and insect distribution mapping.
Landscape ecology adds an important component to the
ecological expertise assembled on the
Molecular Biology of Insect / Plant Host Interactions
This proposed position in the Department of Entomology would
focus on hypothesis-driven research that addresses the molecular basis of
interactions between insects and plants, including interactions that extend to
a third trophic level, such as with symbionts, plant pathogens, entomopathogens,
entomopathogenic nematodes, parasitoids, and predators. The position would have
substantial opportunity to collaborate with strong programs in molecular
biology that currently exist on both the Wooster and Columbus campus, for
example in the Departments of Horticulture and Crop Science, Plant Pathology,
and Plant Molecular Biology Program, as well as interdisciplinary programs in
Molecular, Cellular, and Developmental Biology. The position can expect to
build on a strong tradition of research collaboration between Entomology, the USDA-ARS,
and Department of Plant Pathology focused on the biology and ecology of insect vectored
plant diseases. The highly active Wooster Area Molecular Biology Association (WAMBA)
fosters partnerships `between these departments on the OARDC campus, as well as
inter-institutional collaborations with molecular biologists at the
Spatially explicit simulation: percolation models and
emerald ash borer (Robin Taylor)
Robin Taylor has been studying and modeling the dispersal by
flight of the Emerald Ash Borer (EAB, Agrilus
planipennis Fairmaire (Buprestidae)). Data of EAB
flight performance developed by Taylor and Leah Bauer (USDA-FS-NCRS, East
Lansing, MI) using Taylor’s insect flight mills have now been standardized
using free flight data developed by Keith Windell and James Kautz (USDA-FS
Missoula Technology and Development Center). The distributions of flight speed
estimated from both the flight mill and free flight are very well approximated
by normal distributions with identical variances (t163 = 0.7, p =.05) and
means separated by 3 kph (Figure). This result suggests that our estimates of
the potential range of gravid female EAB must be increased by a factor of
three.
Genetic correlation between diamondback moth behavioral
responses to insecticides and physiological tolerance in larvae (Casey W. Hoy
and Mustapha F. A. Jallow)
Dr. Mustapha Jallow has extended a project on the impact of
insecticides on insect dispersal, and it’s relevance in the development of
resistance. Past work in our lab in this area has concentrated on the larval
stage, whereas Dr. Jallow has focused on adult behavioral responses. Phenotypic
and additive genetic variation in behavioral response and physiological tolerance
to permethrin were measured and reported on at last year’s meeting. More
recently a long-term selection experiment was completed in which we tested the
effects of indirect selection on both larval and adult behavioral responses and
the effects of direct selection on mortality of all life stages.
A field-collected population of diamondback moth, Plutella xylostella (L.), from
Entomopathogenic nematode spatial structure and
dispersal in muck soils (Casey W. Hoy,
Apple of
likely also transported with commodities.
Migration and Dispersal Bibliography
Jallow, M. F. A. and C. W. Hoy. 2005. Phenotypic variation
in adult behavioral response and offspring fitness in Plutella xylostella (Lepidoptera: Plutellidae) in response to permethrin. J.
Econ. Entomol. 98: 2195-2202.
Beanland, L., Madden, L. V., Hoy, C. W., Miller, S. A., and
Nault, L. 2005. Temporal distribution of aster leafhopper (Macrosteles
quadrilineatus) sex ratios and spatial pattern of aster yellows phytoplasma
disease in lettuce. Annals Entomological Society of America 98: 756-762.
S. Ortiz-Garcı´a, E. Ezcurra, B. Schoel, F. Acevedo, J.
Sobero´ n, and A. A. Snow. 2005. Absence of detectable transgenes in local
landraces of maize in
Stuart, R. J., M. E. Barbercheck, P. S. Grewal , R. A. J.
Taylor , and C. W. Hoy. 2006. Population Biology of Entomopathogenic Nematodes:
Concepts, Issues and Models. Biological Control. In Press
Jallow, M. and C. W. Hoy. 2006. Quantitative genetics of
adult behavioral response and larval physiological tolerance to permethrin in
diamondback moth Plutella xylostella (Lepidoptera: Pluutellidae) J. Econ. Entomol. 99(4):
1388-1395.
Jallow, M. and C. W. Hoy. Indirect Selection for Increased
Susceptibility to Permethrin in Diamondback Moth (Plutella xylostella)
(Lepidoptera: Plutellidae). In Press.
2006 State Report for
NCERA-148
Scott A. Isard,
Major Participants in Movement and Dispersal Research: Annalisa Ariatti (Plant Pathology), Dennis Calvin (Entomology),
Eric DeWolf (Plant Pathology), Howard Fescmeyer (Biology), Shelby Fleischer (Entomology), Paul Knight (Meteorology), David Mortensen (Crop
Science), Doug Miller (Geography), and Joe Russo (ZedX).
Active Movement and Dispersal
Programs at PSU.
1. Soybean Rust. Primary PSU players are Scott
Isard, Joe Russo, Eric DeWolf, Annalisa Ariatti, and Paul Knight.
Collaborators include Glen Hartman, Monte Miles (ARS,
2.
3. Wheat Fusarium Head Blight. Primary PSU
participants are Erick DeWolf, Paul Knight, Gretchen Kuldau, Doug Miller and
Mizahu Nita. PSU graduate students associated with project include Julio
Molineros and Katlyn Tilley.
4. Glysophate-Resistant Horseweed. Primary PSU
participant is David Mortensen. Collaborators include Elson Shields
(Cornell), Mark VanGessel (
5. Citrus Greening. Primary PSU participants are
Scott Isard and Joe Russo (ZedX)
Incomplete List of Movement and Dispersal Grant Activities at
1. Aerial dispersal of soybean rust spores: An
aerobiological model to forecast the spread of Phakopsora pachyrhizi at global, continental, and regional scales. CSREES NRI Animal and Plant Biosecurity Grant
Program. $900,000 to conduct field
studies on aerobiology of soybean rust in
2. Weather-based assessment of
soybean rust invasion of
3. Soybean Rust Monitoring Activity for the National Legume Risk Management
Tool Development Project. RMA/CSREES Interagency Agreement to PSU for $185,000 for 2006.
4. Citrus Greening
5.
Hopper
as an interactive online decision support system. Joe Russo ( ZedX),
Dennis Calvin and Scott Isard (PSU), Nelson Foster and Robert Quartarone
(USDA-APHIS-PPQ). APHIS-PSU Cooperative
Agreement for $99,000 established for 2006.
6.
Meeting
the needs for leaders in agricultural biosecurity. USDA-CSREES
grant for $138,000 to PSU Department of Plant Pathology, 2005-2008. Co-PIs include Barb Christ, Seogchan Khan,
David Geiser and Scott Isard
7.
Aerobiology modeling for and documentation of the
2006
Incomplete List of Relevant Publications (2005-present)
Dauer J.T., D.A. Mortensen and R. Humston,
2006. Controlled experiments to predict
horseweed (Conyza canadensis)
dispersal distances. Weed Science 54:
484-489.
Fleischer, S. G. Payne, T. Kuhar, A. Herbert, Jr., S. Malone, J. Whalen,
G. Dively, D. Johnson, J.A. Hebberger, J. Ingerson-Mahar, D. Miller and S.
Isard, In Press. H. zea trends from the northeast:
Suggestions towards collaborative mapping of migration and pyrethroid
susceptibility. Plant Health Progress.
Isard, S.A., N.S. Dufault,
M.R. Miles, G.L. Hartman, J.M. Russo, E.D. De Wolf, and W. Morel, 2006. The effect of solar irradiance on the
mortality of Phakopsora pachyrhizi
urediniospores. Plant Disease
90:941-945.
Websites related to NCERA-148
objectives maintained by PSU/ZedX researchers:
Computational Epidemiology and Aerobiology Laboratory (CEAL) www.ceal.psu.edu
Pan-American Aerobiology Association:
www.paaa.org
USDA Citrus Greening website: citrusgreening.com
USDA Soybean Rust Information system (Public website) sbrusa.net
USDA Soybean Rust Information system (Restricted access website) aphis.zedxinc.com
Measurable Impacts:
The USDA Soybean Rust
Information System transitioned into the Pest Information Platform for
Extension and Education (PIPE) for 2006 and expanded to include soybean
aphid. The PIPE concept developed by
Scott Isard, Joe Russo, and Erick DeWolf (http://www.plantmanagementnetwork.org/sub/php/review/2006/platform/)
has its roots in NCERA-148 discussions and NCERA-148 sponsored workshops and
symposia starting with the
Towards the Integration of Monitoring
and Modeling of Migratory Lepidoptera
Shelby
J. Fleischer, Howard Fescmeyer, Scott Isard, & Doug Miller
Our goal is to strengthen and expand monitoring
networks, integrate them with a modeling infrastructure, and coalesce this
information for delivery of pest risk maps. We focus on corn earworm and sweet corn as a model system, with a
design that facilitates rapid inclusion of other migratory lepidoptera.
Regional monitoring delivered through interactive
cartography. Funds
requested through the Environment Institute are being used at the local
(county) level. Eighteen Extension Educators (listed in Table 1) used
interactive cartography to map population density-activity of migratory
Lepidoptera using pheromone-baited traps at up to 38 sites during the field
season. Traps and lures were provided by
Penn State Entomology. Extension
educators established field sites, entered data on-line, maps and time-series
graphics were updated daily, and information delivered at www.pestwatch.psu.edu
(an example page shown as Figure 1).
Commentary about the maps, and supporting management information, was
written and uploaded weekly into the same website, from June 17 to August
22. Information delivery was also
accomplished through 1-800-PENNIPM and an e-newsletter distributed by the
Pennsylvania Vegetable Grower’s Association.
Geographic expansion and Model Development.: Progress was made towards
developing a similar monitoring network throughout Midwestern states and into
Ecological genetics research support. The infrastructure described
above was used to collect samples from which we plan to search for population
variation using microsatellites, through Drs. H. Fescmeyer (Penn State Biology
Dept.) and O. P. Perrea (USDA ARS, Stoneville MS).
Soybean Rust Research at PSU during 2006
(Scott Isard, Erick DeWolf, Annalisa Ariatti &
Joe Russo)
Escape of soybean rust spores from
a soybean canopy (Jeremy Zydek, M.S student in PSU Inter-college
Ecology Program). The objective is to quantify the
relationship between turbulence and canopy structure on Phakopsora pachyrhizi urediniospore escape from a soybean
field. The field measurement program was
conducted in two phases: 1) particle
releases from a point source in a PA soybean field under ambient conditions
using DayGlo NG-20 paint chips to simulate soybean rust spores and 2) field
measurements of P. pachyrhizi escape from a diseased plot of soybeans
(non-point source) under ambient conditions in
Microclimate and rate of within
field soybean rust spread (Justin Dillion, Ph.D student in
Plant Pathology). This project has a number of interrelated objectives: 1)
Determine the effects of row spacing (7, 14, 30 inch rows) on microclimate
variables in soybean canopies in
Wet and dry deposition of soybean
rust urediniospores (Nick Dufault, Ph.D. student in Plant
Pathology). The first objective of this
research is to determine the percentage of wet and dry deposited spores that
are retained in the lower, mid and upper soybean canopy levels. The second
objective is to examine the effects of environmental factors (rain intensity,
and wind) and cultural practices (row spacing) on the distribution and
retention of spores throughout the soybean canopy.
Adhesion of Phakopsora pachyrhizi urediniospores to soybean (Maria Valez, M.S. student in Plant Pathology). The objectives of this
research are to: 1) Determine the timeline of Phakopsora pachyrhizi spore adhesion to soybean leaves, and 2)
Determine the nature of the adhesion process and its chemical components. The research is being conducted in
collaboration with Dr. Doug Luster (ARS) under strict quarantine conditions
within a containment facility located at the USDA-ARS,
Evaluation of spore trapping as
an early warning system. In collaboration with Glen Hartman and Todd Steinlager (ARS National
Soybean Research Lab,
Winter scouting of kudzu for
soybean rust. Between January and April 2006, every known soybean rust infected kudzu
patch in
Ensemble Aerobiology
Modeling of Soybean Rust Spread. The objective was to integrate and interpret
aerobiology model simulations conducted by multiple research teams to provide
support for tracking the spread of soybean rust during the 2006 growing season.
Output from the PSU/ZedX Integrated Aerobiology Modeling System, the St.
Louis-Iowa State climate model, and the NOAA ARL HYSPLIT trajectory model was
interpreted by a team of trained agricultural meteorology interns from PSU
meteorology department. The student team
under the direction of Paul Knight (PA State Climatologist) electronically
manipulated the model simulations and interpreted the ensemble of outputs to
create easy-to-understand, online products for delivery to researchers,
extension specialists, and administrators on the restricted access PIPE web site.
2006 State Report for
NCERA-148
1. Early-Season Dispersal of
Cotton Fleahoppers Relative to Atmospheric Factors
The cotton fleahopper (CFH), Pseudatomoscelis seriatus (Reuter), is an early-season pest of
cotton which occasionally achieves major pest status. Abrupt, unpredictable fleahopper infestations
complicate cotton pest management. A field
study was conducted in the Brazos River Bottom production area of
Figure 1. Sticky trap placed next to a plot with
substantial growth of turnipweed at the Storey Orchard (SO) site.
Seasonal patterns of
capture of CFH at
Storey Orchard 2005 Storey Orchard 2004
Figure 2. Capture of cotton fleahoppers on the upwind
side of the upwind traps (black bar) and downwind traps (white bar) at
Acknowledgment
Ritchie Eyster,
Sharon Mowery,
Impact
Researchers captured cotton fleahoppers within and around plots of
turnipweed, a suspected weed host, but determined that turnipweed is not a
significant source of fleahoppers that subsequently disperse to infest cotton.
2.
NSF-ITR: Advanced Imaging and Information Technology for Assessing the
Ecological and Economic Impact of Brazilian Free-tailed Bats on Agroecosystems
Thomas H. Kunz, Gary F.
McCracken, Thomas G. Hallam, Margrit Betke, Cutler J. Cleveland, and
OBJECTIVE:
To quantify seasonal production of crop pest
insects and their availability as a food source for Brazilian free-tailed bats
in the Texas Winter Garden.
APPROACH:
Seasonal Observations
