Intraguild interactions between the predatory mites Neoseiulus californicus and Phytoseiulus macropilis (Acari: Phytoseiidae)

• Ano de defesa: 2017
• Autor(a) principal: Porto, Morgana Maria Fonseca
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Phytoseiulus macropilis; Neoseiulus californicus; Tetranychus urticae; Controle biológico; Predação (biologia); Ciências Agrárias; Agronomia; Fitossanidade; Entomologia Agrícola
• Link de acesso: http://www.locus.ufv.br/handle/123456789/11825

Predatory mites are commonly used as biological control agents and the species Phytoseiulus macropilis and Neoseiulus californicus have been considered to be released together to control an important pest, the two-spotted spider mite Tetranychus urticae. Because interacting predators may interfere with each other, an important step towards the implementation of successful release of multiple predators in biological control programs requires to resolve how predators respond to the presence of each other and whether they are involved in intraguild interactions. Given this, initially, I investigated whether these two predatory mites avoid the presence of each other. It is known that predators and parasitoids can use volatiles associated with the presence of competing species when foraging for patches with prey or hosts. I therefore investigated whether the two predator species use volatiles emanating from plants with prey and heterospecifics to avoid prey patches with the other predator species. Furthermore, I assessed whether these predators interact trough intraguild predation, in which competing predators also kill and eat each other. However, because there is no consensus regarding criteria to evaluate the occurrence of such interaction, I first explored existing criteria and suggested guidelines for the design of experiments. Based on these guidelines, I subsequently evaluated both the capacity of P. macropilis and N. californicus to kill stages of the other species and the capacity to benefit from feeding on these stages, both prerequisites for the occurrence of intraguild predation. The most important findings regarding the possible interactions among these predators are that neither of the predators used volatiles to avoid prey patches occupied by the heterospecific predators. However, they did engage in reciprocal intraguild predation. Moreover, I show that ontogeny clearly played a critical role in determining the occurrence of intraguild predation within this predator system. I discuss the possible explanations for the lack of odour-mediated avoidance and the interplay between ontogenetic stages and intraguild interactions.