Submitted after 6/12 deadline:
All spiders are carnivorous, and prey are presumed to be a spider’s source of energy for maintenance, growth, and reproduction. Having observed nectar feeding in Cheiracanthium inclusum (Miturgidae) and Hibana velox (Anyphynidae), however—both nocturnal running spiders that wander in vegetation—I brought C. inclusum into the lab to see if nectar, which is high in carbohydrates, contributed to a spider’s livelihood other than as source of water. A diet of extrafloral nectar, without prey (water ad lib.), significantly increased the survival of newly-emerged spiderlings. It also maintained the nightly running activity of spiderlings; those receiving water only became increasingly quiescent and died. Added to a diet of prey (Drosophila), nectar contributed significantly to survival and molting. Given these positive contributions, I predicted that in field conditions in which nectar is available and accessible, spider nectar feeding should be common activity, at least among Hibana and Cheiracanthium. Cotton crops provide a good environment to test this prediction. Both genera of spiders inhabit the crop, and the cotton plant has extrafloral nectaries on its leaves and flower bracts, which make nectar accessible to arthropods (such as ants and spiders) that may not typically visit flowers. Collections from a USDA cotton crop in Weslaco, Texas bore out my prediction: one third of 325 wandering spiders tested positive for fructose, a plant-derived sugar, even long after peak nectar production. Not only did Cheiracanthium inclusum and two species of Hibana test positive, so did the locally abundant crab spider Misumenoides (Thomisidae).
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