[Syrphidae] Re: Sex identification based on abdomen coloration
Wouter van Steenis
w.v.steenis at casema.nl
Wed Feb 10 14:19:41 GMT 2016
Dear Malin and others,
For Eristalis arbustorum I’m quite convinced that it is by far more easy to distinguish males and females in the field than to distinguish between females of Eristalis arbustorum, E. abusiva (in Europe) and E. brousii (in North-America) and between males of these species. It is not only the color distribution, but also the brightness of the orange spots. And males tend to have more hairy bodies. However, there is a rather small proportion of really dark males and really light females that do overlap in coloration.
So in my opinion anyone who claims to have recognised one of these species in the field should for sure be able to say what sex it was.
In E. tenax it is quite difficult due to huge variation in coloration. The males being much more orange, the females being much more black, but with a very extensive overlap. The form of the abdomen might be a bit more helpful, but I only sex them based on the separation of the eyes.
In E. intricarius (hair coloration) and E. pertinax (form of abdomen) it is quite easy to separate almost all specimens.
From: Francis Gilbert
Sent: Wednesday, February 10, 2016 9:24 AM
To: Hoverfly discussion list ; malin.thyselius at gmail.com
Subject: [Syrphidae] Re: Sex identification based on abdomen coloration
Do you know the attached papers? Graham Holloway did a lot of work on the variation in colour pattern in arbustorum, and Jon Heal also on tenax, arbustorum and intricarius
Dr Francis Gilbert
Professor of Ecology
Room B132, Biology Building, School of Life Sciences
University Park, University of Nottingham, Nottingham NG7 2RD, UK
Tel: +44 (0) 115 951 3215
From: syrphidae-bounces at lists.nottingham.ac.uk [mailto:syrphidae-bounces at lists.nottingham.ac.uk] On Behalf Of Malin
Sent: 10 February 2016 08:16
To: syrphidae at lists.nottingham.ac.uk
Subject: [Syrphidae] Sex identification based on abdomen coloration
During this years field season I have started to consider whether the coloration of the abdomen can help in sex identification, particularity of Eristalis tenax and Eristalis arbustorum. My feeling is that the most brightly coloured individuals appear to be male, whereas the individuals with darker colours could be either male or female. Have anyone noted something similar or do you have another way to quickly determine sex in the field (except for the difference in eye morphology, which even though useful can be a bit tricky in some field situations)?
This message and any attachment are intended solely for the addressee
and may contain confidential information. If you have received this
message in error, please send it back to me, and immediately delete it.
Please do not use, copy or disclose the information contained in this
message or in any attachment. Any views or opinions expressed by the
author of this email do not necessarily reflect the views of the
University of Nottingham.
This message has been checked for viruses but the contents of an
attachment may still contain software viruses which could damage your
computer system, you are advised to perform your own checks. Email
communications with the University of Nottingham may be monitored as
permitted by UK legislation.
Syrphidae mailing list
Syrphidae at lists.nottingham.ac.uk
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Syrphidae