Canadian Forest Service Publications

Spatio-temporal variation in mating success of female bagworms. 2013. Rhainds M. Entomologia Experimentalis et Applicata 146: 123–129.

Year: 2013

Issued by: Atlantic Forestry Centre

Catalog ID: 34608

Language: English

Availability: PDF (request by e-mail)

Mark record


The study investigated spatio-temporal variation in the mating success of female bagworms, Thyridopteryx ephemeraeformis Haworth (Lepidoptera: Psychidae), across a broad latitudinal range in Indiana, USA, between 2007 and 2009. A series of interconnected equations based on estimates of demographic parameters at different intervals was used to derive the punctual sex ratio and female mating success early and late in the season. Both the mating success of females and the relative abundance of bagworms declined with latitude, which provides indirect support to the mate encounter Allee hypothesis. However, the late emergence of females at northern locations combined with the consistently low mating success of late-emerging females suggests that the impact of latitude on mating probability is indirectly mediated by emergence time. A variable level of protandry was observed each year, and the low ratio of males per female late in the season was associated with low female mating success. The reduced level of activity of males at temperatures below 18 °C may also account for the low mating probability of late-emerging females. The weak, inconsistent effect of local variation in sex ratio on female mating success suggests that males commonly disperse from their natal patch, a behavior that may have evolved to reduce inbreeding in local populations of bagworms. Altogether, these results suggest that temporal variation in sex ratio has a greater impact on the mating success of female bagworms than spatial variation in sex ratio.

Plain Language Summary

A mathematical model was developed to convert cumulative estimates of proportional data into punctual estimates, to infer temporal life history trajectory of female reproductive output