Spider Egg Sacs Research Articles

Development and Reproductive Behavior of Mantispa viridis Walker (Neuroptera: Mantispidae)

The development and reproductive behavior of Mantispa viridis Walker was examined in northwestern South Carolina. Campodeiform first instars actively searched spider egg sacs and halted the development of spider eggs that had advanced to the prelarval or larval developmental stages. M. viridis utilized both viable and inviable spider eggs and completed development on as few as five black widow, Latrodectus mactans (F.), eggs. Developmental time from eclosion to adult emergence averaged slightly less than 24 d. Both mated and unmated females produced egg clutches. However, viable clutches were only produced by mated females. Mated females produced a greater number of clutches each containing more eggs than unmated females. Unmated females produced a small number of eggs that embryonated, and in which a mantispid larva developed. However, larvae in these eggs did not eclose. Males were found to have the intertergal membranes between abdominal segments 3 and 4, and 4 and 5 expanded. These membranes were everted during courtship and apparently emitted a mating or recognition pheromone. Mating behavior and adult longevity are also described.

Seasonal Phenology and Overwintering of Mantispa viridis Walker (Neuroptera: Mantispidae) in South Carolina

Captures of immatures and adults of Mantispa viridis Walker indicate this species has at least three distinct generations per year in the Clemson area of South Carolina, with an occasional fourth one in late fall and early winter. Mark-recapture studies show that M. viridis adults are rarely recaptured. Experiments exposing adults and immatures to ambient fall and winter temperatures in the Upper Piedmont of South Carolina resulted in the death of all adults by December, but 33% of the larvae emerged as adults the following spring from late February through May. The ability to survive prolonged freezing weather as immatures inside spider egg sacs may allow M. viridis to inhabit the colder regions of its range.

Tetrastichinae (Hymenoptera: Eulophidae) associated with spider egg sacs

Aranobroter rayorae, gen. et sp. n., is described as a gregarious predator of spider eggs within egg sacs of Metepeira incrassata (Araneidae) from Veracruz, Mexico. Baryscapus uetzi, sp. n., is described as an internal parasitoid of A. rayorae. The biology of these two species is discussed. A review of Tetrastichinae associated with spider egg sacs includes new North American records.

Predatory versatility and intraspecific interactions ofSupunna picta(Araneae: Clubionidae)

Abstract Unlike most clubionids, which are nocturnal, drab coloured, hunting spiders, Supunna picta is a highly active diurnal spider with distinctive markings. How this spider interacts with prey and conspecifics was investigated, and the evolutionary significance of this unusual spider’s behaviour is discussed. S. picta is shown to be a versatile predator which not only catches prey cursorially; it also builds a web it uses for detecting prey and invades alien webs where it catches insects and the resident spiders. Unlike some web-invading spiders from other families, S. picta does not use aggressive mimicry when in alien webs. S. picta has a very rapid, erratic style of locomotion which seems to be important in both prey capture and in escape from its own predators. During intraspecific interactions, S. picta performs distinct display behaviours, interactions at and away from webs being similar. Males cohabit with subadult females in webs and mate after they mature. Females make flat, papery egg sacs, more like the egg sacs of many gnaphosid spiders than the typical egg sacs of clubionids.

The function of spider egg sacs in relation to parasitoids and predators, with special reference to the Australian fauna

The function of spider egg sacs is analysed as structures to reduce or prevent mortality by parasitoids and predators. The host relationships of the groups concerned are documented, with special reference to the Australian fauna. Many new records are presented and the biology of each group is discussed. Information presented supports the hypothesis that egg sacs are an effective barrier against scavenging predators (generalists), while coevolution between spiders and their specialized (highly adapted) parasitoids and predators is responsible for the specificity displayed by the latter two groups and the structural diversity evident of egg sacs.

Climaciella brunnea(Neuroptera: Mantispidae): a mantispid that obligately boards spiders

Summary Larvae of Climaciella brunnea (Say) develop within the egg sacs of spiders. In contrast to other species of mantispids whose larvae actively search for spiders or egg sacs, C. brunnea larvae adopt a phoretic posture and wait for spiders to come to them. Larvae are totally unable to directly penetrate egg sacs; they must board a female spider and reach the eggs before they have been enclosed with silk.

Notes on Interactions Between the Spider Eilica puno (Gnaphosidae) and the Ant Camponotus inca in the Peruvian Andes

Sudden overturning of rocks near Puno in the Peruvian Andes revealed intermixed spider egg sacs and Camponotus inca adult ants. The egg sacs contained spiderlings of Eilica puno (Gnaphosidae) with adults found only in C. inca nests. No evidence was seen of behavioral or physical compartmentalization of the spiders and ants. Within two to five minutes after a rock was overturned the ants tralnsported all egg sacs into underground portions of their nests. Spiderlings crawled over the ground and in one instance over a worker without eliciting observable reaction. Possible benefits to the ants or the spiders from the observed interactions are discussed; the spiders probably benefit from these interactions. THIS PAPER DESCRIBES interesting and previously unreported interactions between the gnaphosid spider Eilica puno' and the ant Camponotus inca Emery,2 and outlines hypotheses to explain such interactions.

Megaselia argiopephaga n.sp. (Diptera: Phoridae), an oriental scuttlefly whose larvae feed on spider eggs

AbstractMegaselia argiopephaga n.sp. is described from a single male from Sri Lanka and a series of adults, puparia and larvae obtained from the egg sacs of spiders, of the genus Argiope, in New Guinea.