A comparison of two parasitoids (Hymenoptera: Encyrtidae) of the vine mealybug: rapid, non-discriminatory oviposition is favored when ants tend the host.

The encyrtid parasitoids Coccidoxenoides perminutus Girault and Anagyrus nr. sp. pseudococci (Girault) were compared in the laboratory as parasitoids of the mealybug Planococcus ficus (Signoret).

Testing baits to control Argentine ants (Hymenoptera: Formicidae) in vineyards.

Liquid baits were evaluated for control of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae), and associated mealybug and soft scale pests in California vineyards. In 2003, liquid baits with small doses ofimidacloprid, boric acid, or thiamethoxam dissolved in 25% sucrose water resulted in lower ant and mealybug densities and fruit damage, compared with an untreated control. Similar treatments in a soft scale-infested vineyard showed only a reduction of ant density and fruit infestation in only the boric acid and thiamethoxam treatments.

Opportunistic out-crossing in Nicotiana attenuata (Solanaceae), a predominantly self-fertilizing native tobacco.

Background: Although Nicotiana attenuata is entirely self-compatible, chemical and other floral traits suggest selection for the maintenance of advertisement for moth pollinators.

Results: Experimental exclusions of pollinators from plants with emasculated flowers in natural populations in southern Utah during an outbreak of the hawkmoth Hyles lineata revealed that 24% of the seed set could be attributed to insect pollination, and eliminated wind pollination and apomixis as contributing to seed set. Hence these moths can mediate gene flow when self-pollen is unavailable.

Experimental studies of the host-finding behavior of Trogus pennator, a parasitoid of swallowtail butterflies.

The parasitic wasp Troguspennator (Hymenoptera: Ichneumonidae) attacks larvae in two genera of Papilionidae, Eurytides and Papilio, on plants in a variety of families. The female wasps' responses to food plants, feeding damage, and frass were examined in a series of experiments designed to test the hypothesis that parasitic wasps that specialize on host taxa and seek their hosts in a variety of habitats exhibit fixed responses to host-derived cues and more flexible responses to cues associated only with the hosts' food plants. Naive T pennator females showed no preferences when offered either a choice between two papilionid food plants or a choice between a food plant and a plant not used for food by Papilionidae.