Leafcutter ant 'hitchhiking'

A minor worker rides on a cut leaf

 When watching a foraging trail of Atta cephalodes leafcutter ants, you will likely notice that occasionally a smaller ant will be 'hitchhiking' on a leaf fragment that a larger ant is carrying.  At first look, these ants appear lazy but they are actually providing a critical service to their colony.

In many habitats, these ants are attacked by flies in the family Phoridae.  Female flies alight on leaves in transport, crawl towards the carrier, and lay eggs on the unwitting ant.  When the eggs hatch, they enter the ants body and consume it from the inside out, eventually killing it.  Hence the reason for the seemingly lackadaisical passengers.  A fly is much less likely to land on a leaf with a rider, and if it does it will quickly be chased off.  The minor workers are defending their sisters from aerial parasitoid attacks.

If you are worried about flying parasitoids, for a small fee I will ride around on your shoulders for a day, defending you from various forms of death from above.

First monarch sighting of 2012

A 2010 monarch lays an egg on milkweed

 While the Journey North webpage indicates that my old friend Danaus plexippus has been in Delaware for some weeks, I saw my first female this past week.  The migratory female that I saw was drab colored and ragged, which suggests to me that it may have traveled quite far this Spring.

  Some of the common milkweed that we planted 2 years ago is just barely starting to poke through the soil, but it's a ready target for ovipositing females.  We may have the only Asclepias in the neighborhood, and a female kept circling back and searching for an open spot to place an egg.  The tip of the milkweed ramet below already had 7 pinhead-sized eggs on it!  Monarchs have high mortality in the early caterpillar stages, and milkweed grows quickly from its underground rhizomes, so there should be plenty of food for everyone when they hatch.

Monarchs are good at finding their Asclepias host plant, even when it is barely poking above the ground.