Photojournal - 29 September 2006

Sensory apparatus

On the 29th, I went around outside my condo building looking for macro subjects. My first subject was a jumping spider, most probably Eris. I think that this is probably the same species as the dark spider from my last entry—this one the female and the previous one the male.  
Next, I found a mosquito sitting still on a leaf. I moved my lens in very close for this shot, and was a little surprised that the mosquito didn't flee. When I saw the photo, though, the reason became clear. The mosquito had a couple of legs caught on a spiderweb; the spiderweb wasn't visible in normal light but showed up well under the flash.  

What follows is a detail of that last shot, showing the mosquito's proboscis, maxillary palps, and antennae.

The maxillary palps are the two hairy tubular structures that start from the head going up to the left, but then bend upwards twice until they are pointing at the middle of the upper side of the photo. Maxillary palps are olfactory organs, and one of their jobs is to sense carbon dioxide, which is what attracts mosquitos to creatures like us. This is a male mosquito, however, so his palps are used to smell out suitable flowers or fruits to sip from. Only females take blood meals.

Between and a little below the maxillary palps is the proboscis. In the photo, the proboscis unfortunately is behind the left palp for most of its length, but then it extends to the left where the palp bends upwards. It's the part pointing to the upper-left corner of the photo. The proboscis is a long tube which is used for drinking nectar or blood. It looks like a simple tube, but it is actually a complex assembly of several different structures (particularly in females).

The antennae are the two plumose (feathery) structures coming out of the head right above the eyes; females have less elaborate antennae. The male mosquito uses his antennae primarily to listen for the sound of female mosquitos; they are finely attuned for picking up the wingbeat of their own species only.

Anyhow, that's quite a lot of sensory and feeding apparatus that this fellow carries around on the front of his face, where it all seems pretty vulnerable. Good thing his eyes are right there to watch over it all.

 

Maybe that's what distracted him so much that he didn't see the spiderweb.

Still on the side of the building, I found a Harvestman walking along on a bush. It was a challenge to try to get the full extent of the critter's legs into the photo.

 
I had found both the mosquito and the spider in a small garden beside the building on the cul-de-sac where I live. Lower in the garden, nearer the ground, there were several plants that had obviously been selected based on their colorful foliage. I took several shots of some of these beauties.  
   
   
I'll close with my only other subject of the night, bark peeling off of one of the trees in the garden.  

Next entry, I'll bring you a smattering of photos from various times in the summer.

Your skeeter-shooter,
Tom

 

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