Sex-biased herbivory in Silene dioica. : Which sex is the better resource?

• In cases when sexual dimorphic traits form the target resource of a particular herbivore we would expect the herbivore to select the best resource. We studied the interaction between to specialist insect herbivores Delia criniventris and Caryocolum viscariella that share the same food resource, the floral stems, of their host plant the perennial and dioecious herb, Silene dioica. We studied the interaction on nine islands in a Bothinan archipelago over seven consecutive years. Both herbivores attacked female plants more than male plants (D. criniventris, 32.8% females, 30.7% males; C. viscariella, 4% females, 2% males). The pattern was consistent over years and islands. We also found a number of sexually dimorphic traits suggesting females to be the better resource. We have presented evidence that female-biased herbivory does occur in dioecious plants and, as with male-biased herbivory, it may occur because herbivores utilise the better resource which will vary depending upon feeding strategy. We conclude that in dioecious species we need identify the dimorphism responsible for the sex sustaining the greatest attack rates and avoid being blinded by the expectation of male herbivory.

Ämnesord

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

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

Nyckelord

Terrestrial ecology

Terrestisk ekologi

ekologisk botanik

Ecological Botany

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