Apr 2, 2017
38 ◦F Air Temp
One of the nice things about collecting aquatic insects is that you can collect in the middle of winter. You can also collect terrestrial insects if you know where to look, but aquatic insects are easy – they are in the water. Even though we have a pretty decent layer of snow on the ground the air temperature was warm and we chose to explore a little creek near us – Beaver Brook.
As I said, the temperature was warm – warm enough so that the winter stoneflies were hatching. This one I believe is in family Capniidae – at least I caught a similar one the week before and keyed it out to that family.
We’ve been doing a lot of our collecting recently with a small seine we made out of old tent poles and window screen. We then place what we find in a small lidded storage container (like a Tupperware) where we painted the bottom white, so we can see the contrast of the insects. We also pick up stones and pick off critters that catch our attention. In this particular creek the numbers were a little thin, but we found some good specimens.
There were plenty blackfly larvae – all these specks on my hand in this picture are blackfly larvae that came off a rock that I was holding. Yep, we’ll be losing some weight via blood loss when these guys all hatch this spring…
We found three nice fishfly larvae – subfamily Chauliodinae. They look a lot like hellgrammites, but don’t have the gills under each abdominal filament. These guys are active predators and had hefty jaws that would grab the forceps when I was picking them up.
In terms of mayflies – we found a nice example of someone in family Paraleptophebia. These are “crawler” type mayflies – and are identifiable by their cylindrical body shape, and in these guys, their nice long antennae. The real give away, however, are their forked gills – indeed these are known as the fork gilled mayflies. In this family in particular, they have long filamentous extensions on the gills that you can see in this picture.
Altho not an insect, we did catch a few planarians. Planarians are flatworms – they glide along a surface and they have a tube like mouth at the bottom of their body which they use to collect food. Interestingly their digestive system is pretty primitive – they only have one opening so they eat and poop out of the same hole (yet one more reason to be happy you are not a flatworm). The food is distributed throughout their body by branches of their digestive system that reaches all the corners. This can be seen easily in this picture as the dark pattern on the planarian. Planaria are also famous for their powers of regeneration. You can cut a planarian in half and the two halves will regenerate forming two new planarian. Nice, but not nice enough to make up for the fact that you have to poop and eat out of the same hole. On some of these pictures you can also see the “eyespots” that are light sensitive organs.
It was a nice trip – short, nothing earth shattering, but a wonderful way to get out in the off season and poke around in a stream.