Tuesday, July 26, 2011

Ladybird Beetle Larvae

The bizarre insects that invaded the aphid farm in my backyard are the larvae of ladybird beetles.
 Ladybird beetle (Coccinellid) larvae feeding on aphids

   These larvae are from the same family (Coccinellidae) as the familiar Ladybug.  What makes these larvae so bizarre looking compared to the Ladybug's larvae, are the long shaggy white tufts of wax they secrete to cover themselves.  This wax may afford the larvae some protection from ants that are "farming" the aphids...see the paper, "Wax Structures of Scymnus Louisianae Attenuate Aggression From Aphid-Tending Ants".
Lady Beetle Larva Among the Aphids
   Those white waxy tufts may attenuate ant aggression, and maybe they also lessen the aphid's alarm response.  Just look at those aphids busily sucking on the Black Locust stem with that hairy-looking predaceous monster walking and feeding with impunity among them.  Looks like a wolf in the sheep fold.
In the photo below the ladybird beetle larva is hoisting a couple of aphids onto its back. 
 I can only guess that the larva is going to truck them off to a more remote leaf to feast.

Here is a picture of a ladybird beetle larva feeding on an aphid.
   The lady beetle larvae feeding among the aphids must elicit some alarm responses from the aphids.  Notice in the photo below the two aphids to the left of the larva.  One is on the leaf opposite the larva and one is on the main stem.  Both of these aphids each have a droplet of wax on the tip of a peg (cornicle) projecting from their back. This cornicle wax is discharged when the aphids are alarmed and solidify on contact with other objects.  These wax droplets help protect the aphid from predators and parasitoids.  The ladybird beetle larvae must have a way of dealing with the waxy defenses of the aphids.
   Yes, well, those wild-looking wax-wigged critters went away after a few days.  I expect they raided the aphid farm to their hearts content and then went nearby to pupate.  Perhaps the adult lady beetles will soon show up and that should prove interesting, although not as bizarre as the larval stage.

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