Evergreen foliage allows early hatching in a pine processionary moth and escape from predation

• 1. Seasonal variation in leaf quality and climate conditions often imposesconstraints on the temporal occurrence of tree-feeding insect larvae, but the seasonaleffects of predation have received limited attention. In temperate climate zones, both theabundance and activity of predators can be expected to vary over time.2. The study reported herein examined the impact of temporal variation in predatoractivity levels on the life history of an herbivorous insect feeding on a constant foodsource: previous-year needles of Scots pine (Pinus sylvestrisL.). In field experiments,the survival and growth rates of colonies ofThaumetopoea pinivoraTreitschke larvaethat had been manipulated to hatch at three different dates were compared. Eggs ofT. pinivorausually hatch by mid-April in southern Sweden, which is earlier than mostother herbivorous insects that overwinter as eggs in this region.3. Predator exclusion experiments indicated that larvae which hatched later than Aprilexperienced a higher level of predator activity, mainly by ants. The final larval size andthe timing of pupation were not affected by hatching date. First instar larvae were moreextensively preyed on than second instars.4. The life history of herbivore species can be affected by seasonal variation inpredation pressures. This study suggests that early hatching in a lepidopteran speciescan allow a temporal escape from predation during the vulnerable early life stages.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

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