Discrimination Between Parasitized and Unparasitized House Fly Pupae by Females of Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae)

Abstract

Females of Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) laid fewer eggs on parasitized than on unparasitized pupae of the house fly, Musca domestica L. Chemical and/or physical conditions of parasitized pupae are detected by the female’s ovipositor, causing this restraint. These conditions may in part result from the host’s death, caused by earlier parasitization, but other factors are also involved. These may include venom injected by the female parasite before she lays, and internal injury to the host resulting from insertion of the parasite’s ovipositor. The female parasite does not discriminate because of physical or chemical traces on the surface of parasitized puparia, of eggs or a surface wound on the pupa, or of absence of heart beat in the pupa.

Host acceptance and sex allocation of Nasonia wasps in response to conspecifics and heterospecifics

“…How N. vitripennis females gain information has been extensively considered by Wylie (1965Wylie ( , 1966Wylie ( , 1970Wylie ( , 1973 and King & Skinner (1991). Females appear to rely on internal cues of the fly puparia that are associated with the oviposition of a previous female.…”

“…Host acceptance and sex ratios produced under superparasitism have been extensively studied in a variety of species, in particular, Nasonia vitripennis (Walker) (e.g. Wylie 1965Wylie , 1966Werren 1980Werren , 1983King & Skinner 1991;Flanagan et al 1998;. Only a few studies, however, have investigated oviposition behaviour under multiparasitism, and these have dealt almost exclusively with host acceptance rather than sex ratios, mostly focusing on species of solitary parasitoid wasps (e.g.…”

“…These decisions can be affected by many factors such as host quality (size and species), the number of competing females and whether the host has been previously parasitized (e.g. Salt 1935;Wylie 1965;King & Skinner 1991;Godfray 1994;van Baaren et al 1994;Gauthier et al 1999;Darrouzet et al 2007; Lebreton et al 2009). Both are also influenced by the species identity of competitors.…”

Mortalidade de larvas e pupas de Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) e seu parasitismo por microhimenópteros na cidade do Rio de Janeiro, RJ

“…Morgan et al (1981) admitem que às causas incertas da morte de algumas pupas de moscas podem ser acrescentadas as injúrias físicas causadas por animais ou durante a coleta, e infecção por patógenos. De acordo com Cardoso & Milward-de-Azevedo (1995), quando C. megacephala e Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) estão associadas a Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae), a mortalidade na fase de pupa pode também resultar do efeito deletério provocado pela ruptura do pupário do hospedeiro pela fêmea do parasitóide, que segundo Wylie (1965a), é realizada com a finalidade de permitir a ingestão do fluido corporal da pupa da mosca. Do total de pupas resgatadas nos dois locais (Tabela 1), de 5,6% emergiram parasitóides, de 77,6% emergiram moscas e de 16,8% não houve emergência.…”

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“…Werren was studying Nasonia vitripennis, a parasitic wasp in which the first foundress lays her eggs, and then flies off. The second foundress is able to detect whether a host has already been parasitized (Wylie, 1965;Holmes, 1972) and adjusts her sex ratio according to whether she is a first or second foundress (Holmes, 1972;Werren, 1980). Ifa female lays eggs on a host as a second foundress, she usually lays a much smaller brood than the first foundress, and since the foundresses lay eggs sequentially, the second foundress may also respond to the usual sex ratio of single-foundress hosts, which tends to be extremely female-biased (Werren, 1980).…”