American Entomologist (2012) 58, 106-115

Russell F. Mizell III, Peter C. Andersen, Brent V. Brodbeck and Wayne B. Hunter (2012)
Congener response reduces risks from bottom-up and top-down forces: Behavioral parsimony by a xylophage
American Entomologist 58 (2), 106-115
Abstract: Organisms must find food and avoid enemies. Homalodisca vitripennis (Germar) is a primary vector of Xylella fastidiosa, the causal agent of Pierce's disease, a deadly disease of grapevines and other plants. H. vitripennis feeds on xylem tissue depauperate in nutrients and has evolved many specialized physiological and behavioral adaptations. Bottom-up mortality risks to H. vitripennis include starvation and reduced fecundity through loss of quality hosts. Top-down risks include predation, egg parasitism by Hymenoptera, and fungal pathogens. Visual behavior of H. vitripennis in response to congeners, common heterospecifics, and artificial models of conspecifics was investigated. Behaviors and the physical properties of the visual cues involved were characterized. H. vitripennis adults exhibited highly significant, positive responses to conspecifics, a heterospecific species, Oncometopia nigricans, and artificial models the size of adult leafhoppers. Significant response was not observed to a congeneric, Homalodisca insolita, with a smaller body size, or to models of sizes, shapes, and colors other than black and red. Cadavers of leafhoppers placed on a novel and nutritionally poor host plant stimulated H. vitripennis adults to land on branches containing the cadavers. H. vitripennis also landed preferentially on branches containing conspecific cadavers despite the presence of a cadaver of a major predator, Anolis carolinensis lizards, or artificial lures resembling spiders. This consistent visual response was independent of variable bottom-up (host quality) and top-down (predator presence) risks, and it suggests for the first time such parsimonious behavior in insects, i.e., sole use of a live visual cue as a means to reduce mortality risks from bottom-up and top-down forces.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Russell F. Mizell III, Wayne Hunter

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Homalodisca vitripennis