Assessment of Variation in Feeding Behavior by Color Morph in the Asian citrus Psyllid (Diaphorini Citri Kuwayama)

The Asian citrus psyllid (ACP) Diaphorina citri (Hemiptera:Liviidae), vector of huanglongbing disease, displays a high degree of color polyphenism. In the adult stage, ACP exhibits abdominal colors that can be separated into three color groupings: blue-green, grey-brown and orange-yellow. Color morphology has been shown to influence important and energetically costly psyllid life traits including reproduction, dispersion, immune defense and resistance to insecticides. Despite this, it remains unclear how color morphology is correlated with feeding behavior. Understanding variation in feeding behavior of the ACP color morphs is critical to better understanding how ACP populations utilize host-plants and to assess potential risk for transmission of the causal agent of huanglongbing disease. We compared the feeding behavior of the three ACP color morphs by using electropenetrography (EPG). We did not detect differences in the feeding behavior activities at phloem or xylem tissues when comparing the three-color morphs. Furthermore, there were no differences in feeding behavioral parameters before reaching phloem or xylem tissues. Our results suggest energy requirements are similar between color morphs and feeding behavior parameters associated with CLas transmission are potentially similar between color morphs.

Behavior of the Avian Parasite Philornis downsi (Diptera: Muscidae) in and Near Host Nests in the Galapagos Islands

The Avian Vampire Fly, Philornis downsi, has invaded the Galapagos Islands, where it causes high mortality of endemic and native landbird species, including most species of Darwin’s finches. Control methods are under development, but key information is missing about the reproductive biology of P. downsi and the behavior of flies in and near nests of their hosts. We used external and internal nest cameras to record the behavior of P. downsi adults within and outside nests of the Galapagos Flycatcher, Myiarchus magnirostris, throughout all stages of the nesting cycle. These recordings showed that P. downsi visited flycatcher nests throughout the day with higher fly activity during the nestling phase during vespertine hours. The observations also revealed that multiple P. downsi individuals can visit nests concurrently, and that there are some interactions among these flies within the nest. Fly visitation to nests occurred significantly more often while parent birds were away from the nest than in the nest, and this timing appears to be a strategy to avoid predation by parent birds. We report fly mating behavior outside the nest but not in the nest cavity. We discuss the relevance of these findings for the adaptive forces shaping P. downsi life history strategies as well as rearing and control measures.

Tree Preference and Temporal Activity Patterns for a Native Ant Community in an Urbanized California Woodland

Anthropogenic disturbances, including land use change and exotic species, can alter the diversity and dynamics of ant communities. To examine foraging behavior in an urbanized habitat in northern California, we surveyed the presence of 9 ant species on 876 trees across 4 seasons during both day and night in a 9.5-hectare urbanized oak-exotic woodland. Ants were more likely to be observed on native, evergreen trees, suggesting that native evergreen species may help maintain ant diversity. Species showed clear patterns of temporal partitioning of foraging activity. Ant species varied in their use of native evergreen Quercus agrifolia trees across season and day/night axes. Of the 3 ant species most frequently observed, Camponotus semitestaceus was most active during spring and summer nights, Formica moki was most active during spring and summer days, and Prenolepis imparis was most active during both day and night during fall and winter. Liometopum occidentale was the second most active species during summer day and night, and winter day. Our findings demonstrate that an oak-exotic urban woodland in Northern California was able to maintain a native ant community, and strong temporal partitioning within that community.