terrycrynant's picture

Yellow headed hazel sawfly

Observed: 12th October 2009 By: terrycrynantterrycrynant’s reputation in Invertebratesterrycrynant’s reputation in Invertebratesterrycrynant’s reputation in Invertebrates
oct
july
yellow head
Croesus septentrionalis
Description:

One of the caterpillars in the third photo has a yellow head but retains the black pigment in the body.Can anyone give me any information about this.I observed these caterpillars for a few weeks until one day they were all gone.Were they eaten or do they all go to pupate on the same day.

Identifications
Species interactions

No interactions present.

Species with which Hazel sawfly (Croesus septentrionalis) interacts

Comments

Jonathan's picture

I suspect that they do all

I suspect that they do all pupate together, because there is safety in numbers and if you are the last one left on the leaf, I would have thought that the chances of being eaten or parasitized are higher. There is quite a lot of synchrony in nature driven by this. For example,seed production in plants (esp trees) varies a lot from year to year and survival is higher when plants are synchonized and total seed production is at its greatest.

Jonathan
University of Edinburgh and Biodiversity Observatory (OU)