During this Spring Break, our lab made a short trip to the Drying Bed in Arlington. This is our first time sampling Daphnia in Texas. This site is a waste water treatment facility and there are a few large ponds. These ponds probably exist all year long and are different from the temporary ponds that I used to sample a lot up in the Mid West and Ontario. Indeed, we found that there are 4-5 different kinds of cladocerans in several ponds combined. We found D. pulex-like species, D. magna, Ceriodaphnia, and probably 2 species of Simocephalus. These ponds have pretty high cladoceran diversity. Another interesting observation is that some species have already started sexual reproduction, with females carrying ephippium and males present in the samples. This is very early timing for sexual reproduction, which in my past sampling experience only occurs in late May or June in the Mid West. We are very interested in identifying the D. pulex-like species and determining its reproduction mode. According to literature, Texas is exclusively occupied by obligately asexual Daphnia pulex. We will find out soon!
