25. lokakuuta 2021

How we learned to tell apart Eupeodes americanus and pomus

More than 400 observations of Eupeodes larvae have been shared on iNaturalist from around the United States and Canada. Based on their distribution, the vast majority could only belong to one of the two widespread Eastern species: Eupeodes americanus and E. pomus. A series of reared larvae recently enabled us to rediscover characters to separate larvae of these two species that were previously described (under synonyms) in Heiss (1938). Many thanks to @molanic @zdanko and @trinaroberts in particular for their help (let me know if I'm forgetting anyone else please).

@nsouc reared an E. americanus about a year ago (iNaturalist#52819675). Along with @zdanko, I reared several Eupeodes americanus in 2021 and two males successfully emerged as adults (iNaturalist#83068603, iNaturalist#96176999). @molanic found several Eupeodes larvae in June and shared them on iNaturalist, where we invited them to study these larvae further. @molanic ultimately reared 13 E. pomus and 15 E. americanus, of which 4 E. pomus and 3 E. americanus successfully emerged. Despite strong differences between the larvae of these species, adults do not noticeably differ except in male terminalia:

E. pomus male terminalia: https://www.inaturalist.org/photos/153537921
E. americanus male terminalia: https://www.inaturalist.org/photos/157406323
E. pomus female https://www.inaturalist.org/observations/93163802
E. americanus female https://www.inaturalist.org/observations/94974788

With the ability to confidently identify the larvae of these species, we now have a dataset of their respective occurrences based on iNaturalist and BugGuide data. You can see maps here:
https://www.inaturalist.org/taxa/625990-Eupeodes-pomus
https://www.inaturalist.org/taxa/460811-Eupeodes-americanus
https://bugguide.net/node/view/2045484/data
https://bugguide.net/node/view/33142/data

Eupeodes americanus larvae are grey to brown in color. Starting in the second instar, they possess a small round patch of small black setae on the side of each abdominal segment. These black setae persist into the puparium and are an easy way to separate larvae and pupae from E. pomus.

E. americanus feeding on Aphis nerii on milkweed in IL:
2nd instar https://www.inaturalist.org/observations/94630689
last instar https://www.inaturalist.org/observations/94632720
pupa https://www.inaturalist.org/observations/94632719

E. americanus feeding on aphids cf. Uroleucon on a yellow composite in MD
1st instar https://www.inaturalist.org/observations/95500012
2nd instar https://www.inaturalist.org/observations/95500005
Last instar https://www.inaturalist.org/observations/95500004
pupa https://www.inaturalist.org/observations/96177020

Eupeodes pomus larvae are yellow to green in color, with bright red and white markings dorsally. Last instars also lack the long bristles typical of E. americanus or larvae with similarly-colored patterning like Dioprosopa clavata or Paragus spp.

E. pomus feeding on Aphis nerii on milkweed in IL:
first instar https://www.inaturalist.org/observations/91681414
medium early instar https://www.inaturalist.org/observations/92015773
later early instar https://www.inaturalist.org/observations/80171846
last instar https://www.inaturalist.org/observations/91575907
fresh pupa https://www.inaturalist.org/observations/91575909
Mid pupa https://www.inaturalist.org/observations/91680956
Late pupa https://www.inaturalist.org/observations/92296961

This last set wasn’t reared but illustrates some of the color variation typical of E. pomus larvae on unusual species of host aphid:
E. pomus feeding on* Aphis craccivora* on redbud in IL:
Last instar https://www.inaturalist.org/observations/18787138
Middle instar https://www.inaturalist.org/observations/18787141

Many other larvae of these species have been photographed and shared on iNaturalist and BugGuide, representing many other aphid and ant hosts.

Heiss, 1938. A classification of the larvae and puparia of the Syrphidae of Illinois, exclusive of aquatic forms. University of Illinois Urbana-Champaign. https://archive.org/details/classificationof16heis/page/132/mode/2up

Lähetetty 25. lokakuuta 2021 22:16 käyttäjältä edanko edanko | 1 kommentti | Jätä kommentti

3. elokuuta 2021

Mating pairs of Xylomya tenthredinoides versus simillima

I previously separated these two species by the amount of red on the hind femur, but photos of mating pairs suggest this isn't a reliable distinction. The following linked mating pairs appear to represent the below species:

X. tenthredinoides
https://www.inaturalist.org/observations/85560188
https://bugguide.net/node/view/1617071/bgimage

X. simillima
https://www.inaturalist.org/observations/48384345
https://www.inaturalist.org/observations/80618876
https://www.inaturalist.org/observations/81167694
https://bugguide.net/node/view/57358/bgimage
https://bugguide.net/node/view/404652/bgimage
https://bugguide.net/node/view/875104/bgimage
https://bugguide.net/node/view/57359/bgimage
https://bugguide.net/node/view/406169/bgimage

Based on these observations and consulting Webb 1984, I propose the following differential diagnosis for the two species:

Lähetetty 3. elokuuta 2021 01:12 käyttäjältä edanko edanko | 2 kommenttia | Jätä kommentti

12. kesäkuuta 2020

Toxomerini - Northeastern USA/Canada

Lähetetty 12. kesäkuuta 2020 16:32 käyttäjältä edanko edanko | 0 kommenttia | Jätä kommentti

24. toukokuuta 2020

Guide to Nematoceran Families

I'm excited to share this guide to families of Nematocera! Questions, suggestions, and other reactions are appreciated. Please let me know if you find any oversights.

Lähetetty 24. toukokuuta 2020 22:22 käyttäjältä edanko edanko | 5 kommenttia | Jätä kommentti

21. toukokuuta 2020

ID Guide for Higher-level Diptera Groups

I'm excited to share this guide to major groups of Diptera! Questions, suggestions, and other reactions are appreciated. Please let me know if you find any oversights.

Lähetetty 21. toukokuuta 2020 23:40 käyttäjältä edanko edanko | 16 kommenttia | Jätä kommentti

19. toukokuuta 2020

Syrphini - Northeastern USA/Canada

@upupa-epops and I are excited to share this guide to common Syrphini of the Northeastern USA/Canada! Questions, suggestions, and other reactions are appreciated.

To help improve identifications using this guide:
https://www.inaturalist.org/observations/identify?taxon_id=121991&place_id=7590,6883,13336,7289,7587,6853,9116,13,44,3,38,24,32,35,26,29,20,31,7,33,39,4,42,51,48,52339

Lähetetty 19. toukokuuta 2020 17:55 käyttäjältä edanko edanko | 6 kommenttia | Jätä kommentti

6. toukokuuta 2020

Syrphini - Southeastern USA

@upupa-epops and I are excited to share this guide to common Syrphini of the Southeastern USA! Questions, suggestions, and other reactions are appreciated.

To help improve identifications using this guide:
https://www.inaturalist.org/observations/identify?taxon_id=121991&place_id=25,12,18,28,36,27,45,37,19,30,43,23,21

Lähetetty 6. toukokuuta 2020 17:20 käyttäjältä edanko edanko | 11 kommenttia | Jätä kommentti

5. toukokuuta 2020

Syrphini - Northwestern USA & Western Canada

@upupa-epops and I are excited to share this guide to common Syrphini of the Northwestern USA & Western Canada! Questions, suggestions, and other reactions are appreciated.

To help improve identifications using this guide:
https://www.inaturalist.org/observations/identify?place_id=13337,9079,13335,7085,6834,7953,46,10,22,16,15&taxon_id=121991

Lähetetty 5. toukokuuta 2020 20:35 käyttäjältä edanko edanko | 19 kommenttia | Jätä kommentti

26. huhtikuuta 2020

Syrphini - Southwestern USA

@upupa-epops and I are excited to share this guide to common Syrphini of the Southwestern USA! Questions, suggestions, and other reactions are appreciated.

To help improve identifications using this guide:
https://www.inaturalist.org/observations/identify?taxon_id=121991&place_id=14,50,40,52,9,34

Lähetetty 26. huhtikuuta 2020 23:34 käyttäjältä edanko edanko | 17 kommenttia | Jätä kommentti

28. marraskuuta 2019

Fly Guide

I've had this linked to my profile for several months, but I thought I might add it as a journal post so that people can add comments and people can tag one another, etc.

I hope this can be useful, and if someone wants to edit or contribute that would be welcome.

https://sites.google.com/view/flyguide/diptera

Lähetetty 28. marraskuuta 2019 21:39 käyttäjältä edanko edanko | 2 kommenttia | Jätä kommentti