Diario de cappaert

iNaturalist is a bit unusual among online platforms. I've only had one kind of interaction in discussions: respectful, thoughtful, and aiming to improve common efforts to sort out diversity.

Pros and cons of primary source keys, and DiscoverLife, in this thread on an Andrena observation:

Several reasons not to visit iNat:

• It is like Facebook, where you spend inordinate amounts of time browsing around, and looking at your own posts.
• If you want to use it to make solid IDs on bees or ants or other speciose taxa, your chances of getting beyond genus are low.
• If you ask iNat to guide you to species ID, the chances of the algorithm being right are low, at least for bees. It will do better on butterflies or anything where a photo contains enough information.

Advantages:

• Networking. If someone is looking for PNW bee enthusiasts, they will find me for sure. And Brianna Lindh, and Lisa Robinson, and Marek Stanton.
• The quality of IDs from other users is variable, but often stellar. e.g., John Ascher or August Jackson for bees. Or zdanko or trinaroberts for syrphids. And the best thing about these folks is that they are conservative - they back you off to genus wherever the photo doesn't nail species (often).
• There are a slew of projects that exploit big data aspects of iNat. E.g. pollinator associations (330 host associations for Bombyus melanopygus for example). E.g., Washington native bee society (1100 records for B. melanopygus).
• For taxa that you don't know - say, collembola or mushrooms - you can at least get close to an answer.
• A big one for me is that iNat is an efficient way for me to catalog my own observations. If I want to find the flies I saw in Michigan, or the Bombus I saw in CT in 2018 - the search is simple.

I could go on. But aside from what iNat does for me, its greatest value is to nurture interest and provide information to nearly 3 million, mostly non-scientist users.

This field season I indulged a curiosity about Andrena astragali, an obligate associate of death camas. I looked pretty hard for this species in stands of abundant Toxicoscordion venenosum in the Willamette Valley near Corvallis. My main finding was that T. venenosum was intensively visited by the dronefly Eristalis hirta; A. astragali was not to be found--until I uncovered just one site (Thanks Tom Kaye) with a lively population of A. astragali. Today I was looking at insects collected from Fisher Butte, a site with acres of death camas and swarms of visiting droneflies, but no history (we have 4 years of data) of A. astragali. But we had one:

One of the things I like about astragali is that the ID is straightforward. DiscoverLife narrows to this species pretty quickly with simple characters, which is an unnecessary step if you know the host plant is death camas.

I had a similar-looking Andrena, one of few (in our study sites) with complete tergal hair bands:

But this was collected from Potentilla gracilis, an argument against astragali. In the key, I get to Andrena auricoma. In the description I am told This small western species is very similar to A, astragali but can be separated from the latter by its smaller size, rhomboidal and feebly emarginate labral process, and its shinier terga. Check, check, check. Gratifying, until someone tells me I am wrong.

I may eventually be good at diagnosis of at least the easier genera. In the meantime, I can appear wherever a species announces itself with a single, unique trait. E.g., Halictus ligatus and Megachile pugnata are unmistakeable for conspicuous genal processes. Another case: In DiscoverLife there are 96 possibles for Oregon Osmia. Osmia inurbana is the only answer for Middle of rim with distinct, narrow, acutely angled, triangular notch in Oregon.

Caveat: the following includes free-association speculation not based on careful reading of literature. This is a journal; I get to do this.

If you are from the east, the WIllamette Valley climate is an adjustment. In Michigan or Connecticut it actually rains in the summer, so you can find many flower-visiting insects on any decent day from April to November. Late summer is particularly rich, as goldenrod and aster flower in dense stands. By contrast, western Oregon is dry from mid-June until mid-fall, and nectar and pollen resources fall to near-zero in most habitats. Any non-honeybee attempting to forage in August is wasting its time.

Unless it lives in the city. In lots of urban areas, floral resources abound. Where I live (Corvallis), most yards are dead grass, but on any block there will be one or two properties jammed with late summer flowers and an abundance of bees and flies. I've seen Halictus, Megachile, Triepeolus, Agapostemon, Melissodes, Bombus, Ceratina, and honeybees. Plus syrphids including Eristalis, Eupeodes, Myathropa, and Syritta. And cabbage, alfalfa, skipper, and gray hairstreak butterflies. There has to be a powerful selective advantage for insects that are active for two or three months beyond the natural wildflower season. For bees this would include larger or better-provisioned broods. For some syrphids, it could mean additional generations. But of course it is also complicated. Consider possible cases.

Halictus ligatus as a species exhibits some plasticity in the colony cycle, which can be multivoltine, with pauses during dry conditions (in southern Florida). Could either feature appear in bees in Oregon's Mediterranean climate? If so, that might amplify reproduction. But what would happen to the sex ratio during the colony cycle? I note that where I am, males are predominant (but not exclusive) in September; these might have minimal effect on populations.

Osmia lignaria of the Willamette Valley is the subject of a just-out publication examining the (impressive) rate of brood cell production over the month or so that nests are active. The life cycle is probably of fixed length; O. lignaria will enter diapause regardless of an extended availability of floral resources. If so, effects of an extended floral season might be indirect, favoring competitors or cuckoo bee enemies.

Eristalis tenax is observable in the Willamette Valley in any month of the year--a longer activity window than other common Eristalis. Scanning iNaturalist observations, it is pretty well represented on wildflowers--esp yarrow and Queen Anne's lace--that occur in dry conditions late in the season. But in a city, these resources are dwarfed by garden landscape plants that are also exploited by E. tenax, which enjoys multiple generations. There is at least the potential that their populations would be significantly augmented by late summer landscape plants, favoring this species over others.

There is some literature on this question - E.g., Temporal dynamics influenced by global change: Bee community phenology in urban, agricultural, and natural landscapes, which reviews fairly scant literature. But urban landscapes deserve consideration, as mini-experiments in adaptation, and as habitats that are expanding with increasing interest in native plant landscaping.

Along these lines, I have the pet idea that it would be really interesting to study pollinators in botanical gardens, which have diverse kinds of flowers in a large area, well defined and generally isolated from other irrigated landscapes.

Below: some August/September flower visitors in Corvallis.

Any field has its daunting terminology. In taxonomy, there is no way around it. A crucial set of traits for bees: surface sculpturing. It has just been pointed out to me that there is glossary of terms, with images: Surface Sculpturing. The source publication is referenced. The terms are particularly useful for ants (shucks!), but still useful the next time you want to know what areolate-rugose means.