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Abstracts - Morgana Maria Fonseca

Type of the Presentation: (Poster)

ABSENCE OF AVOIDANCE OF COMPETITORS IN TWO INTERACTING PREDATORY MITES

Morgana Maria Fonseca¹*, Eraldo Lima¹, Angelo Pallini¹, Arne Janssen²

1 Department of Entomology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil. emails: MMF: morganamaria.fonseca@gmail.com; EL: mothman@ufv.br; AP: pallini@ufv.br

2 Evolutionary and Population Biology, IBED, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands. email: arne.janssen@uva.nl

* Correspondence: morganamaria.fonseca@gmail.com

Arthropod predators are known to use a wide diversity of volatile cues during their foraging activities. The response to these volatiles determines habitat selection and distribution of species, as well as the occurrence and strength of interactions within food webs. For example, chemical cues are known to mediate avoidance of competitors within trophic levels. It is therefore of paramount importance to explore how the response of predators to volatiles associated with potentially interacting species affects their distribution. Predatory mites are commonly used as biological control agents and the species Phytoseiulus macropilis and Neoseiulus anonymus are considered to be released together to control an important pest, the two-spotted spider mite Tetranychus urticae. It is not known how these predators respond to odours emanating from prey patches invaded by heterospecifics, which is important to determine their interactions and, ultimately, their combined effects on the pest. Using a Y-tube olfactometer, we therefore investigated whether these two predatory mites avoid the presence of the other species using the volatiles emanating from plants with prey and heterospecifics. Whereas both P. macropilis and N. anonymus were significantly attracted to volatiles of plants infested with spider mites, neither of the predators avoided volatiles from prey patches occupied by the heterospecifics. The increased joint use of several species of natural enemies for biological control highlights the importance of exploring the mechanisms and functions of volatiles mediating interactions within the third trophic level. Chemical cues have important implications for ecological interactions and evolutionary processes, however, studies of odour-mediated avoidance of competitors are limited to a small number of species, yet deserve more attention.