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 Decreasing number in the dipters?
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| jorgemotalmeida |
Posted on 02-08-2010 15:38
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 Member Location: Viseu - PORTUGAL Posts: 9295 Joined: 05.06.06 |
There is clearly a large decrease in the number of species visible this year. I would dare to say that this was the worst year to collect flies, at least, according to my short experience in collecting them. It is quite unusual compared to the four years I began to collect Flies. This decreasing number in the dipters was already noted by my friend Andrade and Ruud. Dr. Jindrich said the same. I wonder if you also notice in your country this very low number of flies. There are, however, apparently some isolated places where there was an explosion of the individuals of certain species: the case of Salentia spp., and Nemotelus specimens, for example. Perhaps favored by the winter much more rigorous than usual and more extensive. Possibly the very low temperatures in April and May have contributed to this scenario as well. Also the heavy and prolonged rains could be another factor - February was one of the rainiest months of which I am aware, at least here. I would like to hear your opinions, comments and points of view on what you think which are the reasons behind this decreasing in the dipters, if it is your case. A few moments ago, with a great and very pleasant weather, without being baked and without much wind, and with plenty flowered Foeniculum vulgare (fennel) I only found Besseria sp, Exorista cf. segregata, about 3 Cylindromyia spp., and no much more flies. There are many Polistes spp. (Vespidae); Tiphiidae (Hymenoptera); plenty Mordellidae (Coleoptera); Graphosoma spp. (Hemiptera)... but no many flies. And it should have plenty of them! Only in Porto Covo (near Sines - Portugal) I could see some more flies than I could find in any other place. For example, so far I only found one Myopa sp. Usually I used to find much more Myopa species.. Also so far I didn't find any Empidideicus spp. (and they were very common in the 2 last years) and no one Anthomyzidae. There are very few Dolichopodidae and much fewer Tachinidae than usual. Edited by jorgemotalmeida on 02-08-2010 15:48 |
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| jorgemotalmeida |
Posted on 02-08-2010 16:12
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Member Location: Viseu - PORTUGAL Posts: 9295 Joined: 05.06.06 |
Also I would like to hear if in the past very rainy years this situation was verified in the Spring/Summer for the flies.. |
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| cyprinoid |
Posted on 02-08-2010 16:54
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 Member Location: Norway Posts: 1751 Joined: 19.06.09 |
I not sure if total numbers of species or individuals are less than last year, but it is quite different. Most notably, the number of Tachinids I see this year exceeds the that of last year greatly, both species-wise and the number of individuals. (I also see more large moths this year). Very few yellowjackes and sawflies compared to last year. Edited by cyprinoid on 02-08-2010 16:55 Hyperbolizer |
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| jorgemotalmeida |
Posted on 02-08-2010 17:06
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Member Location: Viseu - PORTUGAL Posts: 9295 Joined: 05.06.06 |
it seems North Europe is heating more comparing with the South Europe.. maybe. I would like to hear if any more Northern dipterologists have similar reports with yours. But here in South it is clear: much more fewer flies than usual! And not just in the number of individuals. Yes, it is true that I have found some new genera that I never saw in the last 4 years. However, there are so many common flies that apparently disappeared... |
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| ChrisR |
Posted on 02-08-2010 19:25
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 Administrator Location: Reading, England Posts: 7699 Joined: 12.07.04 |
Recently numbers of flies were good but earlier they were a bit low. Looking at the catches I seem to be catching the same species as last year with about the same numbers too ... so UK isn't great for flies but I am finding what I would expect to find. But I will only know for sure when I identify everything in the winter  One factor that is different is much shorter flowers and less flowers, due to the droughts we have had here - and the cold at the start of Spring/Summer. Manager of the UK Species Inventory in the Angela Marmont Centre for UK Biodiversity at the Natural History Museum, London. |
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| Roger Thomason |
Posted on 02-08-2010 19:54
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 Member Location: Mossbank,Shetland Isles. Posts: 5255 Joined: 17.07.08 |
jorgemotalmeida wrote: it seems North Europe is heating more comparing with the South Europe.. maybe. I would like to hear if any more Northern dipterologists have similar reports with yours. But here in South it is clear: much more fewer flies than usual! And not just in the number of individuals. Yes, it is true that I have found some new genera that I never saw in the last 4 years. However, there are so many common flies that apparently disappeared... You can exclude the small bits of rock in the North Sea where I live as far as heating up goes. We have had a very long spell of cold weather...snowed off and on for 8 months (October - May) and very little sunshine all summer. Fly numbers seem to be about the same as last year, with more Syrphids about. I noted last year was a poor year for these..http://www.dipter...d_id=28035 and that the same may show in other regions...apparently I was right...ish. The number of flies up here fell dramatically today, this was due to yours truly being on the wrong end of a paintbrush all day...lots of white flies...hard to ID them though..  Roger Edited by Roger Thomason on 02-08-2010 20:06 |
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