March of the larvae, continued

The masses of beetle larvae were not the first to infest the grey alders (Alnus incana) this year.  Nearly as soon as the leaves had appeared in April, large numbers of bluish black beetles appeared on them.

Alder leaf beetles (Agelastica alni) feeding on grey alder (Alnus incana) leaves in April.

These alder leaf beetles (Agelastica alni) spent their time consuming large portions of the leaves -- and mating.

Alder leaf beetles mating.

By mid May, some of the female beetles had eaten so much that their elytra (wing covers) no longer fit over their abdomens.

A female alder leaf beetle in May.

These greatly enlarged females must have then gone on to lay numerous eggs, producing the legions of larvae that would be responsible for even more damage to the grey alder leaves.

March of the larvae

Although I encountered one moth larva crossing the sidewalk, the hundreds of other insect larvae that I have seen recently have been (not very surprisingly) on leaves.  What is surprising is that nearly all those larvae have been on the same few leaves. 

A group of alder leaf beetle (Agelastica alni) larvae eating a grey alder (Alnus incana) leaf.

These unfortunate leaves belonged to grey alders (Alnus incana) and hosted groups of 20+ beetle larvae.  The larvae not only shared the leaves, but also kept in tight formations as they ate their way across the leaves...

The beetle larvae on another leaf leaving a sinuous trail.

...leaving behind them trails of small holes.  However, some of the grey alder leaves were riddled with considerably larger holes.  To be continued...