Friday, September 22, 2017

Secrets of An Assassin Bug's Diet, or Beware of First Impressions!

When I went out with the dog, first thing this morning, I noticed a ladybug on one of my milkweeds, so I went inside and grabbed my camera to photograph it.  I just don't see ladybugs very often any more.  The ladybug turned out to be a Multi-Colored Asian Lady Beetle (Harmonia axyridis), which is very disappointing but not too surprising.  This is the species that is displacing so many of our native ladybugs.

As usually happens when I get my camera out, however, I found a couple other things to photograph while I was outside, and I'd like to share one of them with you tonight.

As I was photographing the ladybug, I noticed another orangish red and black insect nearby, a nymph of a Milkweed Assassin Bug (Zelus longipes).  I'm fairly used to seeing these in my garden nowadays, so I didn't pay too much attention to it at first....

Then I noticed the long, small, white insect it was eating.  "Damn!" I thought to myself, "It's a tiny monarch caterpillar!  No wonder I haven't been seeing any larger monarch caterpillars around."

Since I'm a pretty firm believer in "the circle of life", especially when the life forms involved are native, I did nothing but take a couple pictures.  The assassin bug nymph soon finished its meal and started hunting again, but I didn't notice it capture anything else.

Tonight I went through this morning's photos on the computer - and, lo and behold, that wasn't a tiny monarch caterpillar!  The Milkweed Assassin Bug nymph was actually eating a newly molted (still white) leafhopper!  The leafhopper was just so small that my eyes couldn't make out what it actually was until the magic of photography enlarged it for me.

I have no idea which species of leafhopper this was, but all leafhoppers drink plant sap, so this is a perfect example of a predator keeping a plant-eating insect population under control.  (To be brutally honest, of course, the same could be said if the assassin bug HAD actually been eating a monarch caterpillar.)

Once again I had a dope slap moment and had to remind myself not to jump to conclusions when I'm out in the garden, observing.  I am continually amazed at the intricate functioning of the web of life...when we humans can avoid mucking around with it.

6 comments:

Joan Fox said...

Very cool....and I agree about not intervening, but have to confess this spring when I was doing my every morning rounds counting monarch cats-and the count plummeted from a consistent 45-50 in a range of sizes to nothing within 3 days I would have intervened if I discovered anything preying on them. It is tough being a bug.

Corner Gardener Sue said...

Making discoveries from our photos is so much fun! I frequently see things in photos I hadn't noticed while taking them.

Gaia Gardener: said...

Yes, it's tough not to intervene - and I don't always follow my own "rules", but I try to do so, generally. This is yet another instance where I am very glad I refrained from rule breaking!

Thanks for stopping by, Joan!

Gaia Gardener: said...

Sue, I often discover things in photos that I hadn't noticed in real time. Nearby, smaller insects are probably my most common discoveries that way, but unusual prey being eaten is also relatively frequent for me to see.

bittster said...

I think your brutal honesty is necessary! I often hear people complain about how they've created a wildlife friendly garden full of beneficial insects but don't see many butterflies. Well, it's probably because the beneficials are eating all the larvae... which unfortunately happened to nearly all the wild monarch caterpillars around here. I collected about a half dozen eggs and raised them but other than that saw nothing. Hopefully they had better luck elsewhere!
Fascinating pictures as always

Gaia Gardener: said...

Frank, I would be willing to bet a reasonable amount of money that you had at least a few monarchs that made it to adulthood despite the predators in your gardens. The best hiders will be able to hide from us gardeners, as well as from predators, in our gardens.

If we start getting on to the lack of butterflies in our gardens, I think we have to start looking at other causes...like neonics used to grow the plants we buy from the commercial nurseries. I have to drive over an hour away to buy plants that aren't raised with that toxic stuff - and there are few butterflies anywhere around town these days.