Effects of starvation on reproduction of the predacious mite Neoseiulus californicus (Acari: Phytoseiidae)

Abstract

Effects of starvation on gravid females of Neoseiulus californicus were investigated at 20 degrees C and 85% RH. When females that had been reared with abundant prey were swapped, just after laying their first egg, to conditions without any prey and water, they laid 1.8 eggs and survived for 4.3 days. In the body of well-fed females, an egg with eggshell and/or two oocytes were observed in the ventral and dorsal regions, respectively. The larger oocyte had two roundish nuclei and abundant yolk granules, and was enveloped with a vitelline membrane. These two nuclei were not fused but were just close to each other. The smaller oocyte had a nucleus, but had not yet formed yolk granules and vitelline membrane. Females after 12 h starvation had an egg in the ventral region and an oocyte in the dorsal region of the body. After more than 24 h starvation females maintained an oocyte in the dorsal region of the body, but had no egg in the ventral region. The oocyte was filled with abundant yolk granules and contained two irregular nuclei when females were starved for 24 h, but when starved for more than 36 h it contained one irregular nucleus. These findings suggest that (1) gravid females maintained an oocyte in the dorsal region after laying two eggs during starvation, (2) the oocyte was not absorbed during starvation, (3) the oocyte advanced vitellogenesis and the fusion of two nuclei, and (4) the vitellogenic oocyte was not enveloped with an eggshell and had not started embryogenesis.

Age‐ and temperature‐dependent oviposition model of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) with Tetranychus urticae as prey

“…2004; Escudero and Ferragut 2005; Canlas et al. 2006; Gotoh and Tsuchiya 2008, 2009; Toyoshima et al. 2009) and other abiotic factors such as relative humidity (see Walzer et al.…”

Presumed Paternal Genome Loss During Embryogenesis of Predatory Phytoseiid Mites

“…According to an internal observation of starving females (Toyoshima et al, 2009), the vitelline membrane forms around the egg in the body of a starving female (Fig. 7c).…”

“…2b) and starts vitellogenesis in the dorsal region (also see details in Toyoshima et al, 2000). Although the exact timing has not been confirmed, the penetration of sperm into the oocyte seems to occur when the oocyte occupies the dorsal region (Toyoshima et al, 2009). Following the completion of vitellogenesis (Fig.…”

“…Gravid mothers under starvation were observed at 12-h intervals to confirm the absorption of female oocytes and/or eggs in the mother's body (Toyoshima et al, 2009). When gravid mothers just after depositing the first (male) egg were restricted to no prey items, the mothers did not hold an egg in the uterus but held 1-2 eggs in the dorsal region (refer to Fig.…”

<p><strong>Effects of temperature on development and reproduction of <em>Neoseiulus bicaudus</em> (Phytoseiidae) feeding on <em>Tetranychus turkestani</em> (Tetranychidae)</strong></p><p><strong><em><br /></em></strong></p>

“…Both the development and the predatory action of mites are affected by environmental factors (Palyvos & Emmanouel, 2011;Weintraub et al, 2007;Felton & Dahlman, 1984), including temperature, humidity, rainfall, light intensity, prey, artificial feeding, and fungicides (Domingos et al, 2010;Schütte & Dicke, 2008;Shinmen et al, 2010;Toyoshima et al, 2009;Kawashima & Jung, 2011;Delisle et al, 2014).…”