Fecundity of the pine processionary moth Thaumetopoea pityocampa (Lepidoptera: Notodontidae) at the southern edge of its distribution range
2015
Zamoum, Mohamed | Martin, Jean-Claude | Bensidi, Atia
Analysis of annual and plot variations of egg batches number of Thaumetopoea pityocampa at the southern limit of its distribution area and in Pinus halepensis afforestations situated in the Algerian sub-Saharan region showed that its fecundity depends on the density of its population, plots, years and interaction of plots-years. It appears that the high average abundance of egg batches/trees during the outbreak period of this pest insect exceeds 24. The real fecundity is the lowest in the Mediterranean Basin and suggests that local adaptation can occur. The low fecundity is not an obstacle to caterpillar survival under different selection pressures. It is compensated by merging of colonies during the larval cycle. Moreover, in this study we noted a significant correlation between the number of eggs and the size of egg batches deposited on needles or around small pine branches. Size of egg batches is also intimately linked to the length of adult female forewings, fresh weight of females and weight of their pupae. Females with a biennial cycle have a low potential fecundity compared to those with an annual one.
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