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An examination of the differential production of silk by juvenile male and female Aposthonia ceylonica (Enderlein, 1912) (Embiidina: Oligotomidae)

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Anthony Auletta (Creator)
Institution
Western Carolina University (WCU )
Web Site: http://www.wcu.edu/404.asp
Advisor
James Costa

Abstract: Members of the elusive insect order Embiidina are known for their prolific use of silk, and are unusual among insects in that silk is produced by both sexes and all life stages. However, the relative costs of silk spinning might vary considerably between the sexes, as male embiids do not feed as adults and are thus expected to be more resource-limited than females, which feed continuously throughout their lifetimes. Previous research on this group has also shown that the tarsal silk glands of male embiids contain significantly larger silk reservoirs than those of females, and it has been suggested that juvenile males may use these enlarged reservoirs to store silk proteins for use during adulthood, when the amount of energy available for silk production is low. The purpose of this study was to evaluate the plausibility of these conclusions by comparing the silk spinning behaviors of immature male and female embiids in the Indian species Aposthonia ceylonica (Enderlein, 1912) (Embiidina: Oligotomidae). Since this species is gregarious, spinning was also examined in a group context in order to test the hypothesis that males can adjust the amount of silk production in response to group composition, as they may be expected to conserve their own silk in the presence of spinning females. The quantity of silk produced and the amount of time spent spinning were measured over 24 hours for solitary late instar male and female nymphs, as well as for nymphs in single sex and mixed sex groups. The results of this study suggest that juvenile males do produce significantly less silk than juvenile females, but no significant differences were found between groups and solitary individuals or between single sex and mixed sex groups. These findings corroborate the suggestion that males store silk as juveniles, which is likely a strategy to compensate for limited energy availability during adulthood. However, the data do not provide any evidence for social contextdependent silk spinning in the Embiidina. This study is among the first to address these questions in this little-studied insect order, but further research which incorporates more species of embiids as well as field observations is necessary to fully assess sex-related differences in silk production.

Additional Information

Publication
Thesis
Language: English
Date: 2012
Keywords
Aposthonia ceylonica, Embiidina, Sexual dimorphism, Silk, Social behavior, Social context
Subjects
Embioptera