scholarly journals RELATIONSHIP BETWEEN ESCAPE SPEED AND FLIGHT DISTANCE IN A WOLF SPIDER, HOGNA CAROLINENSIS (WALCKENAER 1805)

2005 ◽  
Vol 33 (1) ◽  
pp. 153-158 ◽  
Author(s):  
Matthew K. Nelson ◽  
Daniel R. Formanowicz
2000 ◽  
Vol 78 (2) ◽  
pp. 265-270 ◽  
Author(s):  
José Martín ◽  
Pilar López

Theoretical models of escape behavior suggest that the optimal distance at which an animal starts to flee (approach distance) increases with distance to the refuge. However, the extent of reliance on refuges may strongly affect this relationship. The lizard Psammodromus algirus escapes a predator by fleeing into leaf litter, which is very abundant but not a safe refuge because the predator could still locate and capture a concealed lizard. We test the hypothesis that escape decisions of this lizard species are based on the conspicuousness of individuals and the type of refuge used, rather than on the distance to cover per se. A field study showed that approach distance was not significantly correlated with distance to available refuges or distance actually fled. However, the type of microhabitat and the type of refuge used influenced the approach distance. Lizards started to flee earlier in microhabitats where they were presumably more visible to potential predators. Lizards ran to refuges that were similar in quality to, but farther from, the nearest available one. A longer flight may be needed to mislead the predator. However, because fleeing may be costly, the flight distance should be optimized. Thus, lizards ran farther and faster when they fled through unsafe microhabitats. Lizards with a low body temperature have lower escape performance and their approach distances should be greater. However, although air temperature affected escape speed, it was not significantly correlated with approach distance or flight distance. The relatively low reliance on refuges by P. algirus indicated that the expected relationship between escape decision and distance to the refuge did not exist. However, the results indicate that P. algirus optimizes its escape decisions according to the costs of fleeing and the costs of remaining.


Author(s):  
A Laino ◽  
S Romero ◽  
M Cunningham ◽  
G Molina ◽  
C Gabellone ◽  
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2005 ◽  
Vol 33 (3) ◽  
pp. 857-861 ◽  
Author(s):  
Shawn M. Wilder ◽  
Jill DeVito ◽  
Matthew H. Persons ◽  
Ann L. Rypstra

Nature ◽  
1974 ◽  
Vol 251 (5475) ◽  
pp. 502-503 ◽  
Author(s):  
W. F. HUMPHREYS

2012 ◽  
Vol 90 (6) ◽  
pp. 714-721 ◽  
Author(s):  
J.J. Bowden ◽  
C.M. Buddle

We studied populations of three tundra-dwelling wolf spider (Lycosidae) species to determine reproductive trait relationships and developmental timing in the Arctic. We collected 451 Pardosa lapponica (Thorell, 1872), 176 Pardosa sodalis Holm, 1970, and 117 Pardosa moesta Banks, 1892 during summer 2008. We used log-likelihood ratio tests and multiple linear regressions to determine the best predictors of fecundity and relative reproductive effort. Female body size best explained the variation in fecundity and body condition was the best predictor for relative reproductive effort. We tested for a trade-off between the allocation of resources to individual eggs and the number of eggs produced (fecundity) within each species using linear regression. There was variation in detectable egg size and number trade-offs among sites and these may be related to local variation in resource allocation linked to density-related biotic or abiotic factors. These findings contribute to knowledge about the fitness of arctic wolf spiders in the region of study and are particularly relevant in light of the effects that climate changes are predicted to have on the arctic fauna.


2008 ◽  
Vol 86 (7) ◽  
pp. 648-658 ◽  
Author(s):  
A. Aisenberg ◽  
F. G. Costa

Allocosa brasiliensis (Petrunkevitch, 1910) is a nocturnal wolf spider inhabitant of coastal dunes. Pitfall-trap data suggested the occurrence of two sympatric and synchronic morphs, with differences in adult size and abdominal design (minor and major morphs). Previous studies performed with the major morph of A. brasiliensis, postulated courtship-role and sexual size dimorphism reversal for this spider. In the present study, we compare data on development and morphology and test reproductive isolation between morphs of A. brasiliensis, with the hypotheses that the two morphs are reproductively isolated and both show courtship-role reversal. As had been reported for the major morph of A. brasiliensis, the minor-morph females approached the burrows of minor-morph males, entered, initiated courtship, and after copulation, males closed their burrows with female cooperation from the inside. Females did not court or copulate with males belonging to the other morph and, in two cases, major-morph females cannibalised minor-morph males. Morphometrical and developmental data showed differences between morphs. The occurrence of copulation only between individuals of the same morph confirm reproductive isolation, supporting the occurrence of two species. Morphological and behavioural data are consistent with courtship-role-reversal hypotheses for the minor morph, constituting the second report in spiders of this atypical behaviour.


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