SEASONALITY AND LIFE-CYCLES OF WOODY PLANT-FEEDING NOCTUID MOTHS (LEPIDOPTERA, NOCTUIDAE) IN MEDITERRANEAN HABITATS

1. The annual cycle of noctuid moths feeding as larvae on the foliage of eighteen woody plant species (belonging to ten different families) was studied at two southeastern Spanish Mediterranean forest habitats. Two questions were addressed in this study. (1) Does the rigorous (ho t and dry) summer season characteristic of the Mediterranean-type clim ate impose a constraint on noctuid life histories? (2) Are there detec table differences in abundance or phenological patterns between the no ctuid assemblages feeding on evergreen and winter-deciduous trees and shrubs? 2. Regardless of their leaf persistence habit, the majority of woody species studied had short shoot growth and leaf production peri ods in spring. Abundance of noctuid larvae peaked in May-June, shortly after host plants started to produce new leaves. Virtually no noctuid larvae were found on the foliage of the woody species studied at othe r times of year. Abundance and seasonal pattern of occurrence of larva e were similar on evergreen and deciduous food plants. 3. In contrast with the unimodal seasonal pattern exhibited by larvae, the abundance of adult moths (assessed by light trapping) showed two distinct peaks in early summer and early autumn, and a marked minimum in mid-summer. 4. Most woody plant-feeding noctuids recorded in this study (86% of sp ecies, about 95% of individuals) were univoltine. Univoltine species f ell into one of two distinct life history categories, corresponding to pre- and post-summer flight periods. These two contrasting phenologie s were associated with a bimodality in the duration of the pupal stage ('short' versus 'long'), and were closely related to taxonomical affi liation at the subfamily level. 5. Within the 'short' pupal duration g roup, some species mate and oviposit shortly after emergence and pass the dry season in the egg stage, while others remain as potentially ac tive, non-reproductive adults over most of the summer and mate by the end of that season. Species in the 'long' pupal duration group pass th e summer in pupal or prepupal stage. 6. In the Mediterranean habitats studied, the adversity of the summer dry season seems to have led to a woody plant-feeding noctuid species assemblage almost entirely made u p of univoltine species that concentrate their larval phases when suit able food (young leaves) is most abundant, and 'avoid' mid-summer as a flight time by emerging either shortly before or shortly after the ad verse summer drought period. Year-round foliage availability afforded by dominant evergreen plants does not seem to have influenced the seas onal organization of noctuid cycles in any substantial way.