Expression of α-latroinsectotoxin in Latrodectus geometricus is not dependent on feeding

The brown widow, Latrodectus geometricus, is an invasive species now widely distributed in North America. Widow spiders are well known for their highly toxic venom that includes a variety of proteins. Among these is the insect-specific toxin α-latroinsectotoxin (α-LIT) which is used to immobilize prey and may be used to avoid predation. Previous studies have shown that life stages aside from the adult stage do express toxins including α-LIT. However, it is still unclear whether expression of this toxin occurs before and after feeding. In this study, we analyzed the expression of α-LIT in individual spiderlings both before and immediately (1 h) after feeding. The data collected indicate that expression of this toxin does not vary between fed and unfed spiderlings and is therefore expressed throughout the life stage. The production of α-LIT requires a large expense of energy for L. geometricus spiderlings because it is a high molecular weight protein so the data signifies that α-LIT is a necessary investment for spiderling survival. Although expression presence did not vary between spiderlings or relative to feeding, it is possible that expression of α-LIT could vary before and after feeding in adults or could vary between the sexes at the spiderling stage. Our results further the existing knowledge of these insect-specific widow toxins in widow biology and provide further insight into their utility for biopesticide development.