ArticlePDF Available

ANYPHAENA (ARANEAE, ANYPHAENIDAE) OVERWINTERING ON LOWEST LIMBS OF WHITE OAK

Authors:
David W. Boyd at Bob Jones University
David W. Boyd
Download full-text PDF
Read full-text
Download citation

Abstract

Juvenile Anyphaena sp. were collected from overwintering traps placed on the lowest limbs of white oak, Quercus alba, in South Carolina. Multiple regression analysis was used to determine that the number of juvenile Anyphaena sp. found can be predicted by the circumference of the limb, the distance from the trunk and the distance from the ground. This study helps demonstrate that the limbs of trees, although often neglected in overwintering studies, can provide a refuge for arthropods.
Content uploaded by David W. Boyd
Author content
All content in this area was uploaded by David W. Boyd on May 19, 2015
Content may be subject to copyright.
40
2003. The Journal of Arachnology 31:40–43
ANYPHAENA (ARANEAE, ANYPHAENIDAE) OVERWINTERING
ON LOWEST LIMBS OF WHITE OAK
David W. Boyd, Jr.: USDA, ARS, Small Fruit Research Station, Poplarville,
MS 39470 USA
Will K. Reeves: Department of Entomology, Clemson University, Clemson,
SC 29634 USA
ABSTRACT. Juvenile Anyphaena sp. were collected from overwintering traps placed on the lowest
limbs of white oak, Quercus alba, in South Carolina. Multiple regression analysis was used to determine
that the number of juvenile Anyphaena sp. found can be predicted by the circumference of the limb, the
distance from the trunk and the distance from the ground. This study helps demonstrate that the limbs of
trees, although often neglected in overwintering studies, can provide a refuge for arthropods.
Keywords: Anyphaena, overwintering, Quercus alba
Many spiders enter a dormant stage during
winter conditions (Schaefer 1977) and those
that overwinter on the trunks of trees are often
surveyed by collecting the spiders with card-
board wrapped around tree trunks (Tamaki &
Halfhill 1968; Tedders 1974; Fye 1985;Mizell
& Schiffhauer 1987; Pekar 1999; Horton et al.
2001). However, the species collected in the
trunk traps are not necessarily the same spe-
cies that are collected during warmer months
from the limbs of the same trees (Peka´r 1999;
Horton et al. 2001) and the limbs are usually
neglected when sampling for overwintering
species. Our research was conducted to deter-
mine if the limbs of white oak trees, Quercus
alba L., were suitable for arthropods to over-
winter, and, if so, where on the limbs they
overwintered.
METHODS
We made traps of gray coroplast (corrugat-
ed plastic, similar to cardboard) by cutting a
sheet of coroplast into sections 15 cm long by
3–3.5 cm wide, providing six longitudinal
cavities in each trap. We placed traps on three
mature white oak trees, Quercus alba L., on
30 October 1998. One tree was located in
Pickens County, South Carolina on the Clem-
son University campus. Two trees were locat-
ed in Greenville County, South Carolina, one
on the Bob Jones University campus and the
other at Reedy River Falls Historical Park.
Trees were selected based on ease of acces-
sibility. Three sets of traps were placed on
limbs greater than or equal to3minlength:
one trap set was proximate to the trunk, one
was in the middle of the limb, and one was
on the terminus of the limb. Two sets of traps
were placed on limbs shorter than 3 m in
length: one trap set was proximate to the trunk
and one on the terminus of the limb. We
placed traps around the limb 2.5 cm apart,
parallel to the limb, and held them in place
with gray duct tape. The diameter of the limb
determined the number of traps around the
limb. Two groups of traps were place around
the limb 3–6 cm apart, one offsetting the other
(Fig. 1).
We used 5 limbs on the oak tree in Pickens
County, each with 3 sets of traps. On the tree
at Reedy River Historical Park in Greenville
County we used three limbs, each with 2 sets
of traps, and on the tree at Bob Jones Uni-
versity we used two limbs, each with 3 sets
of traps. We used a total of 27 traps. The num-
ber of limbs used was based on the number
of limbs reachable at each location with a 3
m ladder. For purposes of regression analysis
the average circumference of the limb at each
trap (circumference at both ends of the trap
set divided by 2), the distance of the trap from
trunk, the distance from the trap to the ground,
and the branching of the limb from the trunk
to the trap were measured. The bark surface
was rated on a scale of 1–3, where 1
5
smooth and 3
5
rough.
41BOYD, Jr. & REEVES—ANYPHAENA OVERWINTERING ON WHITE OAK
Figure 1.—One set of coroplast strip traps.
Traps were removed 24 February 1999 after
three consecutive days of average daily tem-
peratures near freezing (
6
1
8
C) (average tem-
perature for Greenville County was 0.9
8
C for
22–24 Feb. and
2
0.4
8
C for Pickens County).
Traps were placed in plastic bags, taken to the
lab and placed in the freezer. Specimens were
removed from the traps, separated, preserved
in 80% ethanol and identified. Voucher spec-
imens were placed in the Clemson University
Arthropod Collection.
Juvenile Anyphaena sp. were the only ar-
thropods found in numbers large enough to
conduct multiple regression analysis. The total
number of Anyphaena sp. collected was 340.
Multiple regression analysis was conducted
using Minitab. The dependent variable was
the number of Anyphaena, which was stan-
dardized for each trap set by dividing the total
number of Anyphaena by the total number of
traps in each set. The independent variables
were average circumference of the limb, dis-
tance from the trunk, distance from the
ground, number of branches per limb, and
bark surface scale for each trap set.
For multiple regression analysis on Any-
phaena no transformation of the dependent
variable was needed. A tolerance test showed
multicolinearity between polynomials of the
independent variables and the independent
variables. Therefore, only the raw independent
variables were used in the analysis. Stepwise,
forward, and backward model selection tech-
inques all provided the same model. The mod-
el showed no systematic patterns, no outliers,
and no evidence of lack of fit.
RESULTS
Spiders were the most numerous arthropods
collected. All the arthropods collected are list-
ed in Table 1. More Anyphaena sp. were col-
lected near the trunk than the terminus of the
limbs (Table 2).
The multiple regression analysis provide
the following model: Number of Anyphaena
sp.
52
16.1
1
20.3 (circumference of limb)
2
2.74 (distance from the trunk)
1
9.86 (dis-
tance from the ground). This model, with an
R
2
of 70.0%, shows that the number of Any-
phaena overwintering in traps on the bottom
limbs of Q. alba can be predicted by the cir-
cumference of the limb, the distance from the
trunk and the distance from the ground.
DISCUSSION
Schaefer (1977) studied the overwintering
habits of spiders and determined four over-
wintering habit types. Anyphaena sp. is part
42 THE JOURNAL OF ARACHNOLOGY
Table 1.—Arthropods collected from overwintering traps around limbs of white oak.
Class Order Family Species
Arachnida Araneae Agelenidae
Anyphaenidae
Araneidae
Philodromidae
Salticidae
Thomisidae
Coras sp. juv.
Anyphaena sp. juv.
Araneus sp. juv.
Philodromus vulgaris (Hentz)
Philodromus sp. juv.
Eris militaris (Hentz)
Hentzia mitrata (Hentz)
Metacyrba undata (De Geer)
Bassaniana versicolor (Keyserling)
Diplopoda
Insecta Polyxenida
Blattaria
Diptera
Hemiptera
Psocoptera
Polyxenidae
Blattellidae
Syrphidae
Miridae
Ectopsocidae
Polyxenus fasiculatus (Say)
Parcoblatta sp. juv.
Syrphus sp. juv.
Deraeocoris nebulosus (Uhler)
Ectopsocus meridionalis Ribaga
Table 2.—Mean number of Anyphaena sp. juv.
(
6
SE) collected from coroplast traps on white oak,
Quercus alba limbs (South Carolina, 1999). Limb
position is relative to the trunk.
Limb
position Average #
Anyphaena (n)
Proximate
Middle
Terminus
17.4
6
2.0 (10)
12.3
6
2.8 (10)
5.4
6
1.3 (8)
of the majority (45%) of spiders that over-
winter in the juvenile stage (Schaefer 1977).
Tree-dwelling spiders in the genus Anyphaena
are nocturnal wanderers, typically living in fo-
liage from spring through fall, but little of
their ecology or behavior is known (Platnick
1974). They feed on aphids and other prey not
typically active during the day (Marc & Ca-
nard 1997; Marc et al. 1999). Anyphaena spp.
take refuge during the winter but can be active
during warmer days (Turnbull 1960), increas-
ing their ability for survival (Gunnarsson
1985). Other overwintering studies, that in-
cluded Anyphaena spp., sampled only the
trunk or the proximal end of the largest
branch. Bajwa and AliNiazee (2001) found
only four Anyphaena in a four year study.
Horton et al. (2001) found only seven Any-
phaena in a one year study. We demonstrated
that Anyphaena will overwinter on most parts
of the branches with refugia present.
Most refuges available to overwintering
spiders are eliminated when leaves are shed.
Previous studies have shown or suggested that
after leaf-fall spiders move down from the
crown until they find refuge (Duffey 1969;
Horton et al. 2001), which might be the case
with our spiders. The overwintering traps pro-
vided a refuge that otherwise would not have
been available. The diameter of the limbs af-
fected the number of spiders and without ex-
ception, the larger the diameter of the branch
the rougher the bark, which might also pro-
vide refugia.
Horton et al. (2001) collected arthropods
from cardboard bands weekly 23 Aug–07 Dec
1999 in Washington apple and pear orchards.
They found Anyphaena pacifica Banks in
higher numbers (224 total) on a weekly basis
than in overwintering samples (7 total, col-
lected in Jan 2000). They suggested that the
spiders overwinter elsewhere. In Oregon, A.
pacifica was found in low numbers (0.35% of
total catch) during the growing season by
beating the branches over a net (Bajwa &
AliNiazee 2001). In Europe, Marc et al.
(1999) and Marc and Canard (1997) suggested
that A. accentuata (Walckenaer) overwinters
on the tree trunk, but they collected very few
individuals (1% of total catch).
Our study provides information that can be
used in further studies of overwintering ar-
thropods on trees. The branches represent a
large portion of the tree and are often neglect-
ed as a sampling site during the winter
months. Large numbers of spiders on the
limbs could alter decision made in integrated
pest management for landscapes and orchards
such as apple, peach, pear, and pecan.
43BOYD, Jr. & REEVES—ANYPHAENA OVERWINTERING ON WHITE OAK
ACKNOWLEDGMENTS
We thank J. Boyd for technical assistance
and for commenting on an earlier draft of the
manuscript. Thanks also to E. Mockford for
identifying psocids, F.C. Thompson (SEL,
ARS, USDA) for identifying syrphids, F. Coy-
le for identifying salticids, and E. Grissell
(SEL, ARS, USDA) for identifying the chal-
cid wasp. P. Adler, A. Wheeler (both of Clem-
son University), and J. Carroll (USDA, ARS)
made helpful suggestions to improve the man-
uscript, for which we are grateful. This is con-
tribution number 4715 of the South Carolina
Agriculture and Forestry Research System,
Clemson University.
LITERATURE CITED
Bajwa, W.I. and M.T. AliNiazee. 2001. A survey of
spiders in apple trees in the Willamette Valley of
Oregon. Journal of Entomological Science 36:
214–217.
Duffey, E. 1969. The seasonal movements of Clu-
biona brevipes Blackwall and Clubiona compta
C.L. Koch on oak trees in Monks Wood, Hun-
tingdonshire. Bulletin of the British Arachnology
Society 1:29–32.
Fye, R.E. 1985. Corrugated fiberboard traps for
predators overwintering in pear orchards. Journal
of Economic Entomology 78:1511–1514.
Gunnarsson, B. 1985. Interspecific predation as a
mortality factor among overwintering spiders.
Oecologia 65:498–502.
Horton, D.R., E.R. Miliczky, D.A. Broers, R.R.
Lewis, and C.O. Calkins. 2001. Numbers, diver-
sity, and phenology of spiders (Araneae) over-
wintering in cardboard bands placed in pear and
apple orchards of central Washington. Annals of
the Entomological Society of America 94:405–
414.
Marc, P. and A. Canard. 1997. Maintaining spider
biodiversity in agroecosystems as a tool in pest
control. Agriculture, Ecosystems and Environ-
ment 62:229–235.
Marc, P., A. Canard, and F. Ysnel. 1999. Spiders
(Araneae) useful for pest limitation and bioindi-
cation. Agriculture, Ecosystems and Environ-
ment 74:229–273.
Mizell, R.F.,III and D.E. Schiffhauer. 1987. Trunk
traps and overwintering predators in pecan or-
chards: Survey of species and emergence times.
Florida Entomologist 70:238–244.
Peka´r, S. 1999. Some observations on overwinting
of spiders (Araneae) in two contrasting orchards
in the Czech Republic. Agriculture, Ecosystems
and Environment 73:205–210.
Platnick, N. 1974. The spider family Anyphaenidae
in America north of Mexico. Bulletin Museum
of Comparative Zoology 146:205–266.
Schaefer, M. 1977. Winter ecology of spiders (Ar-
aneida). Zeistschrift fur Angewandte Entomolo-
gie 83:113–134.
Tamaki, G. and J.E. Halfhill. 1968. Bands on peach
trees as shelters for predators of the green peach
aphid. Journal of Economic Entomology 61:707–
711.
Tedders, W.L. 1974. Bands detect weevils. Pecan
Quarterly 8:24–25.
Turnbull, A.L. 1960. The spider population of a
stand of oak (Quercus robur L.) in Wytham
Wodd, Berks., England. Canadian Entomologist
92:110–124.
Manuscript received 1 November 2001, revised 15
October 2002.
... Spiders are common components of bark-dwelling invertebrate assemblages (Curtis and Morton 1974; Horton et al. 2001; Horvath et al. 2005; Nicolai 1993) and have been generally reported as a dominant group (Hanula and Franzreb 1998; Horton et al. 2002; Koponen et al. 1997; Majer et al. 2003; Moeed and Meads 1983; Nicolai 1993), suggesting that tree bark plays a significant functional role for this group of predators. However, it is not clear whether spiders use tree bark mainly during specific periods of their life cycle, for example for overwintering (Boyd and Reeves 2003; Duman 1979; Horvath et al. 2004; Pekár 1999) or are permanent residents of this habitat. A number of spider species have been recorded as dwelling on or underneath tree bark in Europe (Koponen 1996, 2004; Koponen et al. 1997; Szinetar and Horvath 2005) and habitat associations of bark-inhabiting species is reasonably well understood (Szinetar and Horvath 2005; Wunderlich 1982). ...
... A large number of arthropod species live on the bark of different tree species, either exclusively or during specific parts of their life cycles, e.g. during overwintering (Boyd and Reeves 2003; Bower and Snetsinger 1985; Horton et al. 2002; Horvath et al. 2004; Pekár 1999). This study is among the first attempts to describe and analyze the barkdwelling spider assemblages in the North American boreal forest. ...
Bark-dwelling spider assemblages (Araneae) in the boreal forest: Dominance, diversity, composition and life-histories
Article
Full-text available
  • Apr 2010
We collected spiders from tree-bark, foliage and litter habitats in deciduous and conifer dominated stands in NW Alberta (Canada) to define these assemblages and consider their conservation significance. To establish habitat associations, we used Indicator Species Analysis (ISA) together with a species dominance metric (DV′) newly proposed here. Of the 116 species collected, 78 were collected from bark. Results support categorizing 16 species as true bark-dwellers, 16 as facultative bark-dwellers and 46 as accidental bark-dwellers or species of unknown association. Species that were strong indicators of particular microhabitats in analyses restricted to bark habitats lost their indicator value when foliage and ground habitats were also considered, suggesting that bark habitats are critical for specific life-history functions. Clubiona canadensis Emerton 1980, Callobius nomeus (Chamberlin 1919), Pocadicnemis americana Millidge 1976 and Enoplognatha intrepida (Sørensen 1888) were the most common bark-dwelling species but their dominance varied among forest cover-types and trapping techniques. Collecting period, forest cover-type, habitat, and trapping technique were generally important environmental variables influencing composition of bark-dwelling assemblages. Although less important in structuring assemblages, tree status (dead or alive) and decay class were important for particular species. Bark habitats are crucial for boreal forest spider assemblages and must be considered central to maintenance of spider diversity.
View
Abiotic factors and biotic interactions jointly drive spider assemblages in nest-boxes in mixed forests
Article
  • Aug 2017
Although spiders are common inhabitants of tree cavities, factors that drive their community structure in these microhabitats are little known. Here we investigated whether bark type, season, intraguild predation (IGP) among spiders, and presence of vertebrate predators can influence the spider community structure in tree cavities. We examined spider abundance and the taxonomic and functional composition of spiders in nest-boxes within two mixed forest stands in central Slovakia in 2012–2013. In total, 1211 spiders belonging to 31 species were sampled from 60 nest-boxes at two sites over three seasons. Spider abundance peaked in autumn as spiders sought wintering sites. Guilds and taxonomic composition changed seasonally with spring and autumn communities dominated by ‘‘Other hunters’’ (Anyphaenidae, Clubionidae, Philodromidae) while during summer the community was dominated by ‘‘Sheet web weavers’’ (Linyphiidae). The guild and taxonomic turnover may be partly explained by the interaction between spiders’ phenology and IGP exerted by winter-active spiders on smaller spiders from autumn until spring. Bark type influenced the guild composition as dominance of ‘‘Space web weavers’’ was higher in trees with rough bark than in trees with smooth bark. The rough bark also reduced the intensity of IGP by Anyphaena accentuata (Sundevall, 1833) on philodromids. The presence of insectivorous birds reduced the abundance of spiders by 67%. The presence of bird predators altered the guild composition as they affected mostly the web spiders. The results show that the biotic interactions and abiotic factors interactively determined the spider community structure in the nest-boxes depending on spiders’ functional traits.
View
Predation activity of two winter-active spiders (Araneae: Anyphaenidae, Philodromidae)
Article
  • Feb 2010
  • J THERM BIOL
Anyphaena accentuata and Philodromus spp. Are cold adapter and winter aktive spider species.Their predation aktivity was investigace dat constant temperatures between –4 and 30C. The lower temperature threshold for Anyphaena was –3.7C, while that of Philodromus was –1.2C. At 1C the latency to capture and prey consumption was significantly porter in Anyphaena than in Philodromus. The capture rate increased with temperature and was maximal at 15C in Anyphaena and at 30C in Philodromus. At 30C, the latency to the capture was significantly porter in Philodromus than in Anyphaena whose mortality significantly increased.
View
View
Trunk Traps and Overwintering Predators in Pecan Orchards: Survey of Species and Emergence Times
Article
  • Jun 1987
Three types of traps placed at ca. 1 m above ground on the trunks of pecan trees from November, 1985 to 15 February, 1986 were compared to pecan bark samples for populations of overwintering predators. Traps were ca. 15 × 100 cm and consisted of the following: 1). burlap trap--modified after Tedders (1974), 2). filter trap--a piece of greenhouse Coolpad® in a UV protected plastic bag with holes, 3). cardboard trap--modified from Tamaki and Halfhill (1968). An equivalent area of bark was the control. A portion of the traps were dissected for their contents in the laboratory. Other traps were retained in cardboard emergence boxes under Albany, GA field conditions and emergence of the predators was recorded in Spring 1986. The coccinellid beetle, Olla v-nigrum (Mulsant), a green lacewing, Chrysopa nigricornis Burmeister, and spiders were found consistently in the traps and the bark. Low numbers of larvae of the brown lacewing, Micromus posticus (Walker), a mirid, Deraeocoris nebulosus (Uhler), the anthocorid, Orius insidiosus (Say), and miscellaneous reduviids were also detected. Earwigs, Doru taeniatum (Dohrn). Forficulidae, were ubiquitously present on the trees. A late season pentatomid pest of pecan nuts and agronomic crops, Nezara viridula (L.), overwintered in the traps in higher numbers than in the bark. Overall, spiders and O. v-nigrum occurred at higher numbers in the traps while more C. nigricornis overwintered in bark. Fifty and 90% of O. v-nigrum had emerged by 3 March and 21 March, respectively. Fifty and 90% of C. nigricornis had emerged by 30 March and 11 April, respectively. /// Se compararon poblaciones de depredadores invernantes usando tres tipos de trampas puestas aproximadamente 1 m del suelo en los troncos de árboles del "pecan" (árbol americano parecido al nogal) de Noviembre 1985 al 15 de Febrero de 1986, con muestras de la corteza del pecan. Las trampas eran de aproximadamente 15×100 cm y consistían de lo siguiente: 1) trampa de saco--modificada de acuerdo con Tedders (1974), 2) trampas de filtro--un pedazo de Coolpad® de invernadero, protegido de los rayos ultravioletas por una bolsa plástica con huecos, 3) trampas de cartón--modificada de acuerdo con Tamaki y Halfhill (1968). Un área equivalente de corteza fue el control. Una porción de las trampas fueron disectadas de sus contenidos en el laboratorio. Otras trampas se mantuvieron en cajas de cartón bajo condiciones de campo en Albany, Georgia, y se anotó la salida de depredadores en la primavera de 1986. El escarabajo coccinélido, Olla v-nigrum (Mulsant), el crosopo verde, Chrysopa nigricornis Burmeister y anañas, se encontraron consistentemente en las trampas y en la corteza. También se detectaron bajos números de larvas del cresopo pardo, Micromus posticus (Walker), el mírido, Deraeocoris nebulosus (Uhler), el antocórido, Orius insidiosus (Say), y misceláneos reduvíidos. Tijeretas, Doru taeniatum (Dohrn), Forficulidae, estaban ubicuamente presentes en los árboles. Tarde en la temporada, una plaga de pentatómidos del fruto del pecan y de otros cultivos agronómicos, pasaron el invierno en números más altos en las trampas que en la corteza. En total, arañas y O. v-nigrum invernaron en la corteza. El 50 y 90% de O. v-nigrum salieron el 3 y 21 de Marzo respectivamente. El 50 y 90% de C. nigricornis salieron el 30 y 11 de Abril respectivamente.
View
The Spider Population of a Stand of Oak ( Quercus robur L.) in Wytham Wood, Berks., England
Article
  • Feb 1960
  • CAN ENTOMOL
In an assessment of spider predation on insects, an arbitrarily delimited woodland community was examined to determine the species of spiders present and their abundance and distribution therein. Periodic samples were taken from September, 1954, to September, 1956.
View
Some observation on overwintering of spiders (Araneae) in two contrasting orchards in the Czech Republic
Article
  • May 1999
  • AGR ECOSYST ENVIRON
Overwintering of spiders was studied by means of cardboard trap bands in two different orchards in the Czech Republic, an apple under integrated pest management (in 1993) and an abandoned pear (in 1995). Twenty-seven species of spiders were found to overwinter on tree trunks. The overwintering composition was not very similar to the composition of arboreal spiders detected during spring and summer by beating tree branches. For example, Clubiona specimens occur on ground and canopy in summer but prefer tree trunks to pass winter. Except Clubionidae, three other families, Philodromidae, Theridiidae and Dictynidae, predominated in trap bands. The two study orchards differed in species composition of overwintering spiders as a result of the orchard type (commercial versus abandoned), temporal variation, and the bark structure (rough in pear and smooth in apple). The commercial apple orchard was predominated by small insecticide-tolerant spiders, Theridiidae and Dictynidae, whereas the abandoned pear orchard was dominated by large susceptible species of Clubionidae and Philodromidae. Installation of cardboard bands on young trees with smooth bark may significantly support overwintering of spiders. Distribution of spiders among trap bands of the IPM orchard showed a clumped pattern. It appeared that populations under pressure are spatially distributed. A significant negative correlation was observed between large spiders (Philodromidae) and small ones (Theridiidae and Dictynidae) resulting presumably from interspecific predation. Non-linear models were fitted to these relationships. The relationship between Philodromidae:Clubionidae, Clubionidae:Theridiidae, and Clubionidae:Dictynidae could not be described by correlation. Thus, it is concluded that Clubionidae do not interact with other spiders at overwintering sites.
View
Corrugated Fiberboard Traps for Predators Overwintering in Pear Orchards
Article
  • Dec 1985
  • J ECON ENTOMOL
Predator traps constructed of several layers of corrugated fiberboard effectively substituted for natural overwintering sites for predators in pear orchards. Deraeocoris brevis (Uhler), Hemerobius ovalis Carpenter, and spiders were the major predators taken from the traps. The traps also offer an inexpensive means of collecting and storing overwintering predators.
View
Bands on Peach Trees as Shelters for Predators of the Green Peach Aphid1,2,3
Article
  • Jun 1968
  • J ECON ENTOMOL
When bands on peach trees were evaluated as artificial overwintering sites for beneficial arthropods over a 2-yr period, predaceous Hemiptera, Syrphidae, Neuroptera, Acarina, Araneida, and parasitic Hymenoptera successfully overwintered in moderate to large numbers under the bands. More than 90% of the arthropods using the bands were beneficial. The ratio of overwintering phytophagous mites to predaceous mites was 3:1 in December 1966, but it changed by mid-February 1967 to 11:1 in favor of predaceous mites. When the temperature and relative humidity under and around a black band was monitored, a wide range of temperature (16.7-26.7 and relative humidity (28-58%) was measured at the time of highest air temperature. When arthropod movement was restricted to a limited area of the band, high mortality occurred; when they were allowed to move around the band, the rate of survival was high for most of the species. The spring emergence of the species of parasites, hyperparasites, and syrphids overwintering under the bands was also studied.
View
Numbers, Diversity, and Phenology of Spiders (Araneae) Overwintering in Cardboard Bands Placed in Pear and Apple Orchards of Central Washington
Article
  • Jan 2009
  • ANN ENTOMOL SOC AM
Cardboard bands were placed on pear and apple trees at each of three sites to act as overwintering shelters for spiders. Bands were placed on the trees in late August, at three heights on the tree. One-third of the bands was collected in January to determine what taxa of spiders overwintered in the shelters. The remaining bands at each site were collected and replaced at weekly intervals between late August and early December to monitor phenology of movement into the shelters. More than 2,900 spiders in 10 families were recovered from the winter-collected set of bands. Spiders were collected from all three sampling heights in the trees. The majority of spiders were juveniles, although adults of some Salticidae [especially Pelegrina aeneola (Curtis) and Phanias sp.] were fairly common. The dominant families were Philodromidae (primarily Philodromus spp.) and Salticidae (primarily P. aeneola), comprising 66 and 28%, respectively, of the total specimens. In the weekly collections, >5,600 bands were sampled during the study producing >6,000 spiders represented by 12 families and 30 identified genera. Dominant taxa in the weekly collected bands included Philodromus cespitum (Walckenaer), P. aeneola, Xysticus spp. (Thomisidae), Sassacus papenhoei Peckham and Peckham (Salticidae), Phidippus spp. (Salticidae), and Anyphaena pacifica Banks (Anyphaenidae). Of these taxa, Xysticus spp., S. papenhoei, and A. pacifica were very uncommon in the winter-collected bands, and we infer from these results that these spiders used the bands as temporary refuges only, and overwintered elsewhere. Data obtained from the weekly collected bands suggested that Philodromus spp., Dictyna spp., P. aeneola, and Cheiracanthium mildei L. Koch entered overwintering shelters during the interval between mid-October and mid- to late November. Pear and apple blocks at the same site were more similar in community composition than a common crop species at two different sites. More spiders were recovered from bands placed in the unmanaged and organically managed orchards than from apple and pear blocks that received insecticides during the growing season.
View
Winter ecology of spiders (Araneida)
Article
  • Aug 2009
  • J APPL ENTOMOL
The life cycle of spiders in temperate latitudes (N. Germany) and the adaptations of the species to low winter temperatures were studied. 5 types of life cycle can be distinguished: I. Eurychronous species hibernating in different stages (23% of 277 spiders); II. Stenochronous species reproducing in spring and summer and hibernating as immatures (45 %); III. Stenochronous species reproducing in autumn and hibernating in the egg stage (7 %); IV. Diplochronous species overwintering mainly as adults and reproducing in spring (3 %); V. Winter‐active species (9 %). The developmental cycles are controlled by temperature or photoperiod and can be partly defined by certain mechanisms of dormancy, e. g. retardation of postembryogenesis evocated by short days in spiders of type II (postembryonic diapause), arrest of embryogenesis by high temperatures in type III (egg diapause), and inhibition of the maturation of ovaries induced by short days in type IV (reproductive diapause). Spiders or spider eggs could be supercooled, but were not freezing‐tolerant. They may be adapted to low winter temperatures by their spatial or seasonal distribution, metabolism, or resistance. 84 % of the spiders overwintered in leaf litter or in vegetation near the ground; 7 % remained without shelter in higher vegetation layers. Diapause was characterized by a reduction of oxygen consumption. The supercooling points of some hibernating stages were lowered in response to falling ambient temperatures. Only few spiders were endangered by a high rate of winter mortality. Different strategies of hibernation are realized by safe and endangered species. The advantage of low winter mortality in the former populations can be compensated by high mortality during postembryonic development. Zusammenfassung Zur Winterökologie von Spinnen (Araneida) Es wird eine Übersicht über den Jahreszyklus der Spinnen in den gemäßigten Breiten (Umgebung von Kiel, Schleswig‐Holstein) und die Anpassungen der Arten an die niedrigen Wintertemperaturen gegeben. Nach dem überwinternden Stadium lassen sich 5 Typen des Jahreszyklus unterscheiden: I. Eurychrone Arten, die in verschiedenen Stadien überwintern (23% von 277 Arten); II. Stenochrone Arten mit Fortpflanzungsperiode im Frühjahr und Sommer, die als Jungspinnen überwintern (45 %); III. Stenochrone Arten mit Fortpflanzungsperiode im Herbst, die als Ei überwintern (7%); IV. Diplochrone Arten, die meist als Adulte überwintern und sich im Frühjahr fortpflanzen (3 %); V. Winteraktive (9 %). Diese Entwicklungszyklen werden in unterschiedlicher Weise durch Temperatur oder Photoperiode kontrolliert und können zum Teil mit bestimmten Dormanzmechanismen definiert werden. Besondere Bedeutung hatten eine durch Kurztag bedingte Verlangsamung der Postembryogenese bei Spinnen des Typs II (postembryonale Diapause), Stopp der Embryogenese bei hohen Temperaturen bei Typ III (Eidiapause) und eine durch Kurztag induzierte Hemmung der Ovarienreifung bei Typ IV (reproduktive Diapause). Die Arten oder Entwicklungsstadien hatten eine unterschiedlich große Kälteresistenz (gemessen am Unterkühlungspunkt) und waren nicht gefrierresistent. Am tiefsten konnte das Eistadium unterkühlt werden (bis — 31° C). Die Spinnen sind an die Winterkälte unterschiedlich gut angepaßt. Dies betrifft die räumliche und zeitliche Verteilung, den Stoffwechsel und die Resistenz. 84 % der Arten überwinterten in Laubstreu und bodennaher Vegetation, 7 % frei in der höheren Vegetation. Diapause war mit reduziertem Sauerstoff‐verbrauch verknüpft. Der Unterkühlungspunkt einiger überwinternder Stadien nahm parallel zu sinkenden Umgebungstemperaturen ab. Die Wintermortalität der meisten Arten war im Vergleich zur Generationsmortalität gering. Es lassen sich ‐ durch den Winter ‐ gefährdete und ungefährdete Arten und damit zwei Strategien der Überwinterung unterscheiden. Bei letzterer kann der Vorteil geringer Wintermortalität durch höhere Mortalität während der postembryonalen Entwicklung kompensiert werden.
View
Interspecific predation as a mortality factor among overwintering spiders
Article
  • Mar 1985
Results from field experiments indicate that predation occurs among spruce-living spiders during winter in SW Sweden. Field observations of natural activity showed that Philodromus spp and Pityohyphantes phrygianus together make up 80% of the spiders active on spruce in winter. They are therefore potential predators on other overwintering spiders. Laboratory experiments were performed at +4 C to assess the importance of such predation between spiders. Small spiders (length 2.5 mm) which had a mean mortality of 3% only. Among the small spiders the Erigninae spp seemed to be more vulnerable to predation than other taxonomic groups. Predation also occurred when large P. phrygianus were kept together, but such predation caused mortality of less importance to the spider populations than the mortality among small spiders. Differences in spider density and food availability did not change this pattern. Considerable weight increase occurred in subadult P. phrygianus when fed during winter. This suggests that winter foraging specimens increase their fitness. Interspecific predation among spiders is suggested to be an important mortality factor in natural populations at high spider densities in November and December, when the ambient temperature often is above 0 C and when the density of large spiders is not yet substantially reduced by bird predation.
View
Spiders (Araneae) useful for pest limitation and bioindication
Article
  • Jun 1999
  • AGR ECOSYST ENVIRON
In northern Europe at least, extensive knowledge of the systematics and ecology of spiders leads the authors to consider them as a very suitable group for pest limitation and for biodiagnostic purposes. An examination of both the qualitative and quantitative aspects of perdition by spider populations and communities is discussed as well as the evolution of some human factors occurring in agroecosystems that are likely to induce changes in spider predation such as chemical spraying and cultural practices. Studies addressing the recolonisation of agroecosystems by spiders, taking into account their dispersing abilities and habitat selection are summarised, followed by a discussion of the global efficiency of spiders as predators in such environments, the risks associated with their use and how to maximise their efficiency.The bioindicative value of spiders is presented by referring successively to population level and community level. The growth rate or the reproductive rate observed in natural populations can be correlated with the amount of prey ingested in the field. Thus, these parameters give an indirect estimation of the habitat quality. Two specific field experiments are presented to illustrate this ecological concept. Moreover, the role of spiders as indicators of heavy metal pollution (atmospheric or soil pollution) integrated by organisms living close to sources of pollution is discussed by reference to a set of laboratory and field experiments. Due to the close correspondence between the vegetation architecture and the composition of the associated spider community, it is argued (with a list of examples) that fluctuations in the spider community structure allows the bioevaluation of human disturbances. Based on the composition of the spider communities, methods of ecological classifications of natural habitats in several European countries are presented.
View