Archivos de diario de abril 2023

02 de abril de 2023

The Sawflies

I have collected 51 sawfly over 3 days from a single location. 3 collected 3/31 were discarded due to accidental crushing, leaving 48 larvae. Some had black prickles and some did not, representing different instars. Under a dissecting scope, I noted all from 3/30 have parasites. The parasites vary in size but are all white and oval. Many of the larvae have several parasites. So far there are 4 from 3/31 and 2 from 4/1 that I did not find evidence of parasites. Since collection many have molted, both those with parasites and those that do not appear to have parasites. After molting, I noticed that these later instars do not have prickles. Under the scope, one of the molted sawflies has curled up and has produced a lot of webbed fiber that it appears to be pulling from it's butt. I am curious to see if it will produce a cocoon and if this instar without prickles is the ultimate or the penultimate instar. My hypothesis is that the 4 sawflies that did not appear to have parasites are in fact parasitized but the parasites are either beneath the surface or are maybe smaller and in a location that is hard to see, like beneath a proleg. All sawflies were collected from a group of parking signs. I did not see any larvae in the nearby grass and only noticed 1 on a nearby tree trunk but it was too high up to reach. Some of my hypotheses for why the majority of the sawflies are parasitized:

  1. collection bias: maybe their behavior of climbing upwards conspicuously is abnormal and is induced by parasitism
  2. collection bias: maybe parasitism is much higher in this season
  3. collection bias: maybe the behavior of climbing up a signpost is normal prepupal behavior but the unparasitized sawfly larvae will perform this behavior later or sooner this season
  4. this sawfly species has an incredibly high rate of parasitism

I am looking forward to seeing what the parasite larvae will become and whether the hosts will be killed or survive. I was hoping to collect non-parasitized sawfly larvae to see which species they become, but I think it is unlikely any sawflies will emerge.

Publicado el abril 2, 2023 04:31 MAÑANA por darlingbeetle darlingbeetle | 1 observación | 2 comentarios | Deja un comentario