Complicated, isn't it?
Monday, 7 July 2025
Contradictory spider
I recently wrote about microbiome-mediated spread of the Mirid bug Apolygus lucorum. Hot on the heels of that discovery comes another - the microbiome of the invasive Linyphiid spider Mermessus trilobatus does not contribute to its dispersal and spread.
The Microbiome of an Invasive Spider: Reduced Bacterial Richness, but no Indication of Microbial-Mediated Dispersal Behaviour. (2025) Microbial Ecology, 88(1), 70. https://link.springer.com/article/10.1007/s00248-025-02565-6
Tuesday, 1 July 2025
Entomology Update - June 2025
It's June, so it's Peak Bioblitz. Much of my activity this month has been dominated by organized group visits and walks. Sadly the results have been dented by the heat and ongoing drought.
In the past, 36 moths of 20 species in the garden moth trap on a warm June evening would have felt like a famine, but now it feels like the best I can hope for.
Research reveals a possible basis for the arrival of new bug species in VC55.
Finishing with a bang
After what has been a tricky month, the very last night proved to be the highlight. A tropical night (according to the Met Office), and the max-min thermometer I place in my moth trap recorded a minimum temperature of 20C. And the moths responded - 247 moths of 27 species, three new for the garden - the best result I have had in years. But the moths weren't the best bit! When I turned the trap off at 3am there was a swirling cloud of life surrounding it. The by-catch comprises over 20 species of Hemiptera (which I haven't had time to sort through yet), and I didn't even attempt the Diptera or the beetles (some of which looked interesting). The absolute highlight was a species I've been waiting to see for quite a few years, the Eared Leafhopper, Ledra aurita.
Apart from sleeping, I'd almost welcome more tropical nights.
Saturday, 28 June 2025
Got the stomach for it?
Year by year we see changes in the VC55 bug fauna with new species arriving. In nearly every case this is because of adaptation to new food plants rather than climate as a primary cause (although climate warming probably also contributes). The question is, how do the bugs adapt? Is it due to genetic changes? A new paper describes the adaptation of the Mirid bug Apolygus lucorum to Cotton through changes in the gut microbes (microbiota) rather than waiting for the slow process of genetic change. This could go a long way to explaining how bug distribution is changing so rapidly.
Gut microbiota facilitates the adaptation of Apolygus lucorum (Hemiptera: Miridae) to its host plant. (2025) Journal of Economic Entomology, toaf142.
Tuesday, 17 June 2025
The Pattern
In the past, 36 moths of 20 species in the garden moth trap on a warm June evening would have felt like a famine, but now it feels like the best I can hope for. Of these, two were new for the garden, including this Scarce Silver-lines, Bena bicolorana. This is the pattern I am seeing now - reasonable numbers of species but overall, hugely reduced numbers of insects, and diversity lower than in the past.
Sunday, 1 June 2025
Entomology Update - May 2025
May has been a busy month, dominated by bees. I am thankful for the relief from the spring drought at the end of the month.
Plunging into solitary bees.
A new species(?) for VC55.
Another tip for insect photography.
One day all field guides will be this good. A real gem of a book and at a bargain price. You'd be daft not to buy it.
Unsurprisingly, the solitary bees I have been working with recently have often been covered in pollen (they have a lot to cram into their short adult lives).
Working out where the bees have been.
I'm troubled by the ongoing demise of traditional wildlife groups, the sort that (used to) meet in a village hall once a month. I observe them gradually blinking out, one by one.
Friday, 23 May 2025
Free Range Pollen
Out and about recently I came across this Chocolate Mining Bee, Andrena scotica, with bulging pollen brushes (scopa), so I put my pollen "skills" into action.
95% of the pollen grains in the sample were the lower, triangular-shaped grains. This is either Bird's-foot-trefoil, Lotus corniculatus, or more likely, Horseshoe Vetch, Hippocrepis comosa, which was present on this site. I can't tell the difference between these two and I'm not sure if it's possible without resorting to DNA. The remaining 5% were Cow Parsley, Anthriscus sylvestris, (the upper oval grain). This makes sense as while the entire site was fringed with Cow Parsley, and while it's not that attractive to bees, the sheer abundance of the pollen would make its absence a surprise.
So, within my limited skills, it works! The only thing that occurs to me is that I really didn't learn anything in this analysis that I didn't already know from observing the bees on site. It would be worth doing with bees from unknown sites, but a little behavioural observation in the field goes a long way.
As an aside, I'm also getting good results using dark field illumination for pollen. Can you guess what species this pollen is from (warning: it's a tricky one!)?
Wednesday, 21 May 2025
Where the bee sucks
Unsurprisingly, the solitary bees I have been working with recently have often been covered in pollen (they have a lot to cram into their short adult lives). I took this female Osmia bicornis from the Geranium macrorrhizum which attempts to overrun my garden (I've never rated it much as a wildlife plant but it has filled a gap which the bees have been very grateful for over the last few weeks).
The large orange pollen grains are obvious, but also very distinctive under the microscope:
My favourite so far is Daisy pollen, Bellis perennis:
So far so easy - I know the flowers I have taken the pollen from. But can I identify pollen taken from bees to work out what they have been feeding on? There are several useful websites for identifying pollen. The Global Pollen Project is good, but my favourite is the Northumbrian Bees pollen gallery.
By coincidence, this month's Microscope Club also involved messing around with pollen and as usual, I picked up some useful tips. Size as well as shape is a key feature of identifying pollen grains and the standard is to make sure the pollen is fully hydrated before measuring, thus aqueous media are used. Glycerol Jelly is the standard medium but is a pain to work with, so I'm using Magnacol aqueous mountant. In water alone pollen grains are quite frisky and move around, making photography difficult. The Magnacol mountant contains PVA and is quite viscous, which fixes the grains better.
This is very much a work in progress but it will be interesting to see what I can find as the season progresses (assuming there are enough hours in the day).
Where the bee sucks, there suck I:
In a cowslip’s bell I lie;
There I couch when owls do cry.
On the bat’s back I do fly
After summer merrily.
Merrily, merrily shall I live now
Under the blossom that hangs on the bough.
Tuesday, 20 May 2025
Book Recommendation: Micro ladybirds of Britain and Ireland
One day all field guides will be this good.
In many ways micro ladybirds ("inconspicuous ladybirds") are a perfect group for a field guide. With around 50 ladybird species in Britain, half of these are the familiar spotted ladybirds. The remaining 25 species, the "inconspicuous ladybirds", are the subject of this book. The illustrations are excellent, the descriptions of the identifying features clear and concise and the comparison plates of similar species particularly useful. A microscope is not required to use this guide, all you need is a 10x hand lens, which will reveal most of the structural features of importance.
A real gem of a book and at a bargain price. You'd be daft not to buy it:
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