Estimation of gypsy moth Lymantria dispar (Linnaeus, 1758) population reproductivity in mass outbreak region | Ozolu mūķenes Lymantria dispar (Linnaeus, 1758) populācijas reproduktivitātes rādītāju novērtējums masu savairošanās reģionā
2010
Silins, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Smits, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Gypsy moth outbreaks cause significant damages to forestry and degrade the biodiversity of forest ecosystems. In Latvia, the first mass outbreak of this pest was recorded in 2008 in the city of Liepaja with 40 ha of broadleaved stands completely defoliated. In the summer of 2008 a field survey was carried out to evaluate the female density, fecundity, and egg hatching success. Field experiments were carried out to observe male dispersal ability, using the mark and recapture method. Male flying ability was found to be over 400 m per day. High density of females was recorded (33.8 - 2.5 females per tree) with the average realised fecundity of 436-66 eggs per female. In 2008, no egg parasites were detected and the egg hatching success exceeded 96%. This resulted in potentially 14,231 larvae per tree, capable of repeated complete stand defoliation. In 2009, the fertility rates of gypsy moth as well as the predation pressure, by using moth disappearance method, were studied. Parasitism on larvae and pupae, and the larval survival success and male flying capacity in heterogonous habitats were also studied. Following the recapture rates ( Jolly-Seber mark and recapture method for open populations) the population size was calculated, including the flight dynamics and survival rate for flying males.
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