היומן של matthewvosper

Hello everyone,

Welcome to the summer holidays! There's been a big bump in observations at the end of this month, unsurprisingly. We'll see how August goes. Here's what to look out for in August.

 Observations

July set another record for the number of observations uploaded.

We recorded a provisional 102 species. Highlights included Callicera aurata, Sphaerophoria interrupta, Eristalis similis, a couple of Platycheirus angustatus, Chrysogaster cemiteriorum and Pelecocera tricincta.

 Identifications

We have also delivered a record number of IDs this month.

Despite that, the NeedsID pile has grown considerably. I'm not sure why that should be because we have actually made more IDs per new observation than last month when it grew much less. But hey-ho, the NeedsID pile is still much lower than it was this time last year - the first full month of this project. Here are the usual breakdowns by tribe and the deep dive into Syrphini. For the first time these can show 13 months so from now on we can directly compare where we are this year to the same time last year!

The biggest climbers (with >50obs to start with) were Syrphus (+34%), Melanostoma (+26%), Chrysotoxum (+24%), Xylota (+20%), and Neoascia (+18%). Eristalis increased by 13% which is a lot from a high base - enough to easily reclaim the 'neediest' spot from Platycheirus. The top 5 neediest genera at the moment are Eristalis (1692), Platycheirus (1576), Melanostoma (916), Cheilosia (897), and Eupeodes (545).

 Annotations

As far as annotations go we're a bit down on where we have been recently, but still way up on the 10-20% that was normal before the project.

 Obscured observations

Just over 3% of observations this month had obscured locations, which is quite good. Click here for why this setting poses difficulties for recording schemes and NBN's recommended alternative.

Thanks everyone, it's great to see more and more people chipping in with IDs and annotations for others. There have been people who have not been able to do as much this month (including myself), but others have more than taken up the slack.

Enjoy the summer!

Matt

All data collected on 31st July 2024

Australian hoverflies are a fascinating bunch. The fauna are dominated by the subfamily Eristalinae, there are only just over 30 from the subfamily Syrphinae.

There seem to be a few other species on iNat in Australia that are either undescribed or just not yet known from Australia. There are also a couple of genera where there are significant taxonomic difficulties.

As always when I create something like this I want to stress that I claim no expertise; I simply enjoy learning and investigating these things, and I hope it is worth sharing what I have found. Please let me know of any corrections that need to be made.

Most of the images in the slides below are by @reiner, other observers are credited where their photos appear. Thanks to everyone who has made their pictures available. It's been great engaging with these hoverflies that I can't get close to myself, and the iNat community observing them, from the other side of the world. I was especially delighted when my first response to a request for a photo actually began with the word "G'day" !

Anyway, the slides below include a key to the genera (or some groups of genera) that should help narrow down what you need to look at, and each genus is listed in alphabetical order and treated in one or two slides.

I have based the list of species on those said to be present in Australia in Thompson and Vockeroth's Catalog of the Diptera of Australasia and Oceania, and the Atlas of Living Australia. In a few places there are difficulties, or interesting iNat observations that suggest the presence of species not on the usual lists: I've given some of my own thoughts in those cases, but it should be clear that they are simply my thoughts.

The genus Melangyna (subgenus Austrosyrphus) poses particular difficulties and I have declined to try and indicate how to identify the six listed species. Instead I have given an indication of the diversity of the genus. I hope to do a separate journal post on this group at some point. I have taken a similar approach to Asarkina and Citrogramma.

So here it is: hope it's of some use.

Species or genera discussed [square brackets indicate doubtful presence, or near-Australian species mentioned], (Parentheses give extra informatrion):
Allobaccha monobia, A. siphanticida, [A. amphithoe, possible others]
Allograpta alamaculata, A. australe, A. notiale, A. terraenovae, [possible something else]
Asarkina (only A. ericetarum is listed for Australia but...)
Asiobaccha bicolor, A. notofasciata
Betasyrphus serarius
Citrogramma (C. australe and C. notiale are the two listed species for Australia)
Dideopsis aegrota
Episyrphus glaber, E oliviae, E viridaureus
Eupeodes confrater
Ischiodon scutellaris
Melangyna (Austrosyrphus) (the six species listed for Australia are M. ambusta, M. collata, M. damastor, M. jacksoni, M. sellenyi, and M. viridiceps)
Melanostoma apicale
Paragus crenulatus, P. politus, [P. villipennis]
Simosyrphus grandicornis
Sphaerophoria macrogaster
Xanthandrus agrolas

Hello! Time for our monthly data frenzy, and it's been another fun one.

September is really the last month of hoverfly season: here's what to look out for. Keep your eyes on the ivy. If you are anywhere near East Anglia it would be awesome to get some more Callicera spinolae observations on iNatUK!

Observations

We have now exceeded 100,000 hoverfly observations on iNatUK! Whoop!

And for the first time the number of hoverflies uploaded in August is greater than in July... so another record - over 6000 for the first time.

However this is partly due to a significant number of old observations being uploaded. The number of hoverflies actually observed in August also went up compared to July for the first time, but the number is still slightly lower than July last year.

In 2024 we have already easily exceeded the total number of observations uploaded in any previous year

We recorded a provisional 103 species: highlights including Eristalis abusiva, Pipiza luteitarsis, Brachypalpoides lentus, Epistrophe diaphana, Sphaerophoria rueppellii and a smattering of Eriozona syrphoides

Identifications

We have also delivered another record month for identifications:

Despite that, the NeedsID pile has grown by nearly 1000. Some of you may remember a few months ago I created a method to predict the size of the needs ID pile in the past from the number of IDs and observations. That was verified by correctly matching the data from this project as it came in. Well this month, for the first time, that method failed completely! By that prediction, the number of IDs we added should have been enough to reduce the NeedsID pile slightly. I don't have an explanation for why our IDs have not translated into Research Grade observations at the normal rate: answers on a postcard!

Below is the usual breakdown of the NeedsID pile according to tribe, and the deep dive into the tribe Syrphini. Something that I think is worth noting is that the reduction in the NeedsID pile compared to this time last year is due almost entirely to the huge reduction in Syrphini that we acheived over the winter, and that we have kept on top of. The other tribes have grown back to the same size as last year.

36 genera increased their number needing ID, with 28 unchanged and 7 down. The genera with the biggest % increases (which had >50 obs to start with) are: Sphaerophoria (+59%), Xanthogramma (+38%), Syrphus (+25%), Neoascia (+24%), Rhingia (+17%), Eristalis (+15%), Melangyna (+13%), Meliscaeva (+13%), and Cheilosia (+11%). The increases in Eristalis and Cheilosia from a high base are particularly noteworthy - Cheilosia has leapfrogged Melanostoma to become the third neediest genus. The neediest genera are Eristalis (1940), Platycheirus (1628), Cheilosia (994), Melanostoma (986), and Eupeodes (569).

Annotations

We haven't kept up with annotations quite as well as some previous months, but we're still doing great really.

Obscured Locations

The use of obscured locations dropped to the lowest proportion we've seen for a major month - just 2.3%. That means more usable data for the recording scheme :)

AOB

Usually the NeedsID pile increases for the last time in September, but I do wonder if this year it might go down - that would be cool. If we want to achieve anything like we did last winter we'll have to deal with the neediest genera listed above. I'll be having a think about what events we can do and what resources might help us tackle them. Happy to hear ideas.

If you are new to IDing, or want to get started, a great way to do that is to sort observations at a high level into the right genus - you can use the URL here, and of course feel free to tag in any of the major identifiers of UK hoverflies if you want to discuss an ID. That's particularly helpful at the start of autumn because it will help us tackle particular genera later in the winter.

Happy Autumn syrphing!

(All data collected on 31st Aug 2024)