Egg sac construction by folding dead leaves in Pozonia nigroventris and Micrathena sp. (Araneae: Araneidae) (original) (raw)
Related papers
Ethology Ecology & Evolution, 2007
Extended maternal care is one of the first steps towards sociality in spiders. Females of Anelosimus cf. studiosus care for their egg-sacs and open them to allow the emergence of the spiderlings, which they feed by regurgitation. In this paper we studied the mechanisms underlying egg-sac opening behaviour in this subsocial spider, by exchanging egg-sacs with different degrees of maturation between two groups of females. We also maintained isolated egg-sacs to test the ability of the spiderlings to emerge by themselves. Mothers always cared for the foreign egg-sacs because they were unable to recognize their own egg-sac. Eggsac opening by foster mothers matched the timing at which the mothers would have opened their own egg-sacs. All the mothers ate eggs, but not larvae or nymphs. Spiderlings were unable to emerge by themselves. The timing of egg-sac opening seemed to depend mainly on an internal factor within the mother, but the exact moment of opening appeared to be adjusted by external stimuli generated inside the egg-sac (nymphal movements). Hence, because material factors rather than nynphal moviments are the major stimulers for egg-sac opening, this species would be unable to care for foreign egg-sacs making communal egg-sac care impossible and thus constraining evolution towards more social behaviour.
Spider Parental Care and Awe-Inspiring Egg Sac (Cocoon)
International Journal of Zoology, 2022
Spiders (Arachnida, Araneae) represent one of the largest groups of organisms on Earth with more than 45,000 recorded species found in nearly all terrestrial communities. In these communities, spiders are obligate predators and generalist consumers regulating the density of pests. Spiders have a stupefying array of prey hunting strategies ranging from ambushing to the use of complex silk nares. Spider silk is incredibly tough and can be used for many applications such as wrapping and immobilization, catching prey, as dragline to connect spiders to the web, as ballooning to aid dispersal of juveniles, as shelters in burrows, for mating, and as egg sacs (or cocoons). Typically, spider egg sacs are multilayered, complex structures that physically protect the eggs and hatchlings against parasitoids, predators as well as changing temperatures. Much research has been undertaken to elucidate the ecological role of spiders and the mechanical characteristics of silks. However, few studies have examined the parental care of spiders and the role of egg sacs. is review goes into great detail about spider parental care and the functions of egg sacs.
Candy‐striped spider leaf and habitat preferences for egg deposition
Agricultural and Forest Entomology
1. Candy-striped spiders (Enoplognatha spp.; Araneae: Theridiidae) are among Britain's commonest theridiid spiders and are potential immigrant biocontrol agents of many pests in arable fields. Though the presence of these spiders in proximity to agriculture is dependent on the availability of suitable leaves for their egg deposition, their preference for different plant species and habitat types has not been fully investigated. 2. Candy-striped spiders were observed in leaf-rolls during transect surveys of seminatural habitats (hedgerow, woodland and grassland) adjacent to oilseed rape fields at 10 sites across northeast England in August and September 2021. The local plant community was surveyed and compared against the leaves used by candy-striped spiders via null models. 3. Candy-striped spiders preferentially deposited their eggs in hedgerow, demonstrating relative avoidance of woodland and grassland. They exhibited preference for bramble, common nettle and hogweed leaves, but also used those of dock, ash and blackthorn. Candy-striped spiders appeared to preferentially use leaves with roughly equal length and width and avoided longer, narrower leaves irrespective of their total size. 4. The leaves used by candy-striped spiders are taxonomically broad, but share some morphological commonalities. Candy-striped spiders exhibit some degree of generalism, regularly utilizing suboptimal leaves in sites lacking their preferences. The availability of preferred plants for these spiders in agriculturally proximate semi-natural habitat may enhance their possible contribution to biocontrol.
Behavioural Processes, 2000
Offspring of the spider Amaurobius ferox (Araneae, Amaurobiidae) were provided with trophic eggs of their mother the day after their emergence from the egg sac. This precisely timed egg laying followed after a series of mother-offspring interactions involving specific behaviors. Experiments showed that the trophic egg laying of the mother (providing she is in the appropriate reproductive condition) necessitated not only their presence, but also the stimulating behavior of the spiderlings. By stimulating their mother the spiderlings actually inhibited the normal maturation of the second generation of maternal eggs and prompted the release. Comparing to the trophic egg-deprived clutches, the clutches provided with the trophic eggs developed with higher body mass, earlier moulting and matriphagy. More offspring survived at the matriphagy with the mother normally provisioning the first clutch with trophic eggs rather than with the mother that did not produce the trophic eggs for her first clutch but for her second clutch. By turning her potential second generation into food, the mother increases her reproductive success.
Multiple Lines of Egg Defense in a Neotropical Arachnid with Temporary Brood Desertion
Ethology, 2014
Egg predation is the one of the main costs of brood desertion in many ectothermic animals. When stressful environmental conditions constrain parental activities to only some periods of the day, the combination of physical or chemical defenses may attenuate the costs related to egg loss during periods of temporary parental absence. Females of the harvestman Neosadocus maximus periodically abandon their clutches to shelter or forage. They also cover their eggs with a hygroscopic mucus coat and seem to lose fewer eggs to predation than other syntopic harvestmen whose eggs lack the mucus coat. Using two species of N. maximus egg predators, we demonstrate that eggs whose mucus coat was experimentally removed suffered higher predation rate than eggs whose mucus coat was left intact. We argue that this mucus provides physical protection against egg predators, especially small arthropods. A similar mucus coat has independently evolved in other two clades of Neotropical harvestman in which males care for the eggs and typically leave their clutches unattended for several hours a day. We propose that the presence of multiple lines of egg defense may have evolved as a way of lowering the costs imposed by intra-and interspecific egg predation during periods of temporary brood desertion.
Journal of Zoology, 2001
Hickmania troglodytes, the Tasmanian cave spider, belongs to a relict group with a scattered world distribution, and is of both phylogenetic and zoogeographic interest. It belongs to the superfamily Austrochiloidea (infra-order Araneomorphae) and shares characteristics with more advanced araneomorphs and primitive spiders in the infra-orders Liphistiomorphae and Mygalomorphae. The reproductive behaviour of H. troglodytes (including courtship, mating, egg-sac construction, brooding, emergence, and moulting behaviour) is described, providing the ®rst such account for any member of the Austrochiloidea. Courtship in H. troglodytes is ritualized and involves distinct communicatory gestures (beating with the legs) by the male to identify and protect himself. Males use a pronounced curve in the metatarsus of the second leg to immobilize females during mating; this curve closely matches the contours of the female's cheliceral region. Both courtship and mating are protracted and each can last for over 5.5 h. The egg-sac is large and unusual, with a rigid internal structure that separates the egg mass from the silk walls, while the silk itself seems to be exceptionally resistant to fungal degradation. The young emerge from the egg-sac 8±10 months after laying, a period signi®cantly longer than the typical emergence time of araneomorph spiders (4±8 weeks). It is suggested that the rigid internal structure and the silk of the egg-sacs may help to buffer and protect the eggs and young from biotic and abiotic factors during this extended pre-emergence period.
Orb-web Design of Garden Spider, Argiope Appensa (Walckenaer, 1841) (Araneae:araneidae)
Australian journal of basic and applied sciences, 2011
This study was conducted to describe the stabilimentum structure in the garden spider, Argiope appensa both in field conditions and in the laboratory. The presence or absence of stabilimenta was examined in the field and in the laboratory; the influence of foraging success in stabilimentum building behavior was also investigated. Results from field survey and laboratory experiments show that stabilimenta is not an obligatory component in web building of A. appensa since some spiders did not add web decoration on their webs. The form and occurrence of stabilimenta varied with spider size. Smaller individuals (body size :< 0.6 cm) commonly built discoid (disc-shaped) stabilimenta while larger individuals (body size: >0.6cm) spun strictly cruciate (cruciform) or part of cruciate stabilimenta. Among the juveniles, the stabilimentum size is positively correlated with the spider's body size; hence, larger individuals tend to spun larger discoid stabilimenta than the smaller ones. In the laboratory, well-fed A. appensa built more stabilimenta and more often than starved spiders. These results argue against the prey attraction hypothesis, but not the predator defense hypothesis, since well-fed spiders invested more in stabilimenta than those starved spiders. Also, A. appensa may adjust the structure and frequency of their stabilimenta probably to suit multiple functions throughout their life history. A. appensa are able to increase or decrease their web sizes, capture area (portion of the web with sticky or capture spirals), and mesh height (distance between sticky spirals) in response to changing prey size and density. Starved spiders spun significantly larger webs and capture area than well-fed spiders. In the absence of potential prey, spiders significantly constructed very narrow-meshed webs or tightly spaced capture spirals than in the presence of potential prey. The present study may demonstrate that spiders can manipulate their web architecture in response to different prey availability.
Parasitoid genus-specific manipulation of orb-web host spiders (Araneae, Araneidae)
Ecological Entomology, 2014
1. Araneid spiders of genus Araniella are attacked by three polysphinctine parsitoid wasps Polysphincta boopsTschek, P. tuberose (Gravenhorst), and Sinarachna pallipes (Holmgren). In the present study, the trophic niche of sympatrically occurring parasitoids and the host manipulation they induced were studied. The aim was to identify whether the variation in host response to manipulation is as a result of differences among parasitoids or among host species.
Predatory behavior of spitting spiders (Araneae: Scytodidae) and the evolution of prey wrapping
The predatory behavior of the spitting spider Scytodes sp . was studied in the laboratory, and an ethogram of the predatory behavior was developed . The principal components usually occur in th e order: tapping, spitting, biting, wrapping, feeding. Spitting results in a pair of sticky, zig-zag, transverse bands which pin the prey to the substrate . At the capture site scytodids wrap the prey usin g the typical form seen in the "higher" spiders : the spider holds the prey in both third legs an d alternates the use of right and left fourth legs in applying silk . Prey are eaten at the capture site .