A survey of nectar feeding by spiders in three different habitats

Using cold-anthrone tests, spiders collected in the field were sampled for the presence of plant sugar (fructose). The spiders came from three different habitats: a cotton field, a mixed rape and fava bean field, and a park with flowering woody and herbaceous plants. The percentages of fructose-positive spiders were compared among the different habitats, as well as among the different sexes and ages of Ebrechtella tricuspidata (F.) (Araneae Thomisidae). Out of 745 field-collected spiders, 18.7% were positive for fructose, indicating that these spiders feed on plant nectar. Of the 12 families of spiders represented, individuals from 9 families were positive for fructose: Oxyopidae, Thomisidae, Pisauridae, Salticidae, Lycosidae, Tetragnathidae, Araneidae, Nephilidae, and Agelenidae. All members of the other three families (Linyphiidae, Clubionidae and Theridiidae) were negative for fructose. There were no differences for nectar feeding in spiders among the three habitats: 19.3% of individuals from the cotton field, 16.6% from the mixed rape and fava bean field, and 20.0% in park with flowering woody and herbaceous plants tested positive for fructose. For E. tricuspidata, significantly more females were positive than males (87.5% versus 42.9%); and immatures tested positive at a lower rate than adults (26.5% and 66.7%, respectively).