Journal archives for May 2021

May 14, 2021

Sanibel nature is so great, and so varied

I just spent three weeks on the Gulf Coast barrier island of Sanibel, near Fort Myers, in Lee County, Florida. Sanibel is 65% nature preserve, and the island has many legal restrictions that make it wildlife-friendly.

This was my 10th visit to the island, which I heard about in childhood thanks to a National Geographic article about it. The island is very famous for its shells, but in reality it is wonderful for almost every aspect of nature. And during this visit I saw a lot of species that I had never seen before, as well as several others that I had seen before, but not very often.

Here are a few highlights. I will add others to this list as they occur to me.

My favorite sighting of all was eight manatees at Jensens Twin Palm Marina on Captiva. They were all but one clustered in an overlapping row right by the seawall where a freshwater spring runs into the saltwater of the back bay. They like to gather there to drink the freshwater, and as a result of that, you can see them quite close-up. They are really enormous, and very sweet-seeming; truly they are gentle giants.

Finally got a great view of an alligator. I also got a photo of a live Black Racer, saw one dead, run-over Florida Rat Snake and the shed skin of another one. Saw a couple of Iguanas from a distance and a freshwater turtle from a great distance (too far away to determine the species) as well as a juvenile Gopher Tortoise who has moved into the hotel grounds where we were staying.

The birds are always great on Sanibel, especially the various waterbirds, lots of egrets and herons and a nice Anhinga drying off. I also saw something that I think may have been a Clapper Rail.

Zebra Longwing, Gulf Fritilliary, Great Southern White, Barred White, White Peacock, Monarch.

Slender Brown Scorpions via UV flashlight, thanks to @jaykeller -- so cool

Squareback Marsh Crab
Mangrove Tree Crab
Atlantic Sand Fiddler Crab

Headlight Beetle, also thanks to @jaykeller and his mothing set-up.
Coastal Tiger Beetle, I think.

Shoelace Fern --looks like an armful of green spaghetti nailed to a tree trunk
Lots of cool lichens TBD

Florida Butterfly Orchid -- native and epiphytic
Chinese Crown Orchid -- ground-dwelling, introduced and invasive

For anyone who loves nature, I thoroughly recommend a visit to Sanibel.

Posted on May 14, 2021 02:21 PM by susanhewitt susanhewitt | 6 comments | Leave a comment

Susan Hewitt gives a Zoom talk to the Marine Biological Association of the UK

A couple weeks ago while I was on vacation in Sanibel, Florida I was asked if I could give a Zoom talk about iNaturalist to the Marine Biological Association of the UK, on the morning of Thursday May 6th. The meeting was at 11 am British time, which means it was at 6 am Eastern Standard time. The meeting was called "Marine Biology Live; Citizen Scientist Special".

It meant I had to get up at 4:45 am to be ready. Also the WiFi reception in our hotel cottage was really terrible, but fortunately the weekday manager of the hotel lent me the office key, so I could do the talk from the office, where the reception was plenty good enough. But during the talk, my husband Ed had to put the office lovebird out on the porch, as she kept squawking rather loudly.

At first I had intended to extemporize the talk, which was supposed to be only 10 or 15 minutes in length, but in the end I wrote it out. The MBA is very prestigious, so I wanted to make sure I did a good job, even though I did not have much time. It would be easier to talk about iNat for an hour than to talk about it for only 10 minutes!

My little talk went OK in the end, although I sounded a bit trashed from having to get up so early. The MBA filmed the whole meeting and put it up on their YouTube Channel.

Posted on May 14, 2021 09:19 PM by susanhewitt susanhewitt | 24 observations | 0 comments | Leave a comment

May 20, 2021

Unknown stem galls on Common Mugwort

This is a story about an unknown gall former, and the story is still only partly understood.

Last summer (August 2020) in Central Park and on Randall's Island, I found six stem galls on the very common and extremely invasive weed Common Mugwort, Artemisia vulgaris. The galls look like this one:

@steven-cyclist was with me several times when I found them, and he probably also photographed one or two of them.

I had never noticed these galls on mugwort before 2020, so I photographed them all, but I had no luck working out what the gall-making organism was that had caused the galls to form.

Fortunately iNatter @jeffmollenhauer is a lot more of a thorough and persistent naturalist than I am. Jeff collected some of these galls in New Jersey. Jeff then carefully cut one gall open, and photographed the larva that was inside the gall. It appeared to be a beetle larva:

Jeff also carefully saved a few of the intact galls to see what hatched out in the next spring or summer.

Sure enough, this spring, 2021, beetles started hatching out, like this one:

It is a Tumbling Flower Beetle, in the genus Mordellistena.

However, it seems that the beetle is almost certainly not the original gall former, but instead is an inquiline parasite. Mordellistena is a stem borer and a gall borer, but it does not create galls.

The Mordellistena larva apparently takes over the gall, a gall which is probably initially occupied by, and created by, a Eurosta fly larva. Eurosta are gall flies, and they are the causal agent of some similar galls on Golden Rod species. For example this large gall, which was caused by the Goldenrod Gall Fly, Eurosta solidaginis:

After an initial gall is formed on Common Mugwort, then presumably a mother Mordellistena beetle lays an egg on the outer surface of the gall. That egg hatches and the young beetle larva chews its way into the gall. The beetle larva starts out by eating the soft inner tissues of the gall, and then probably it often goes on to eat the little Eurosta larva too! Talk about eating you out of house and home!

For more info on this type of interaction, read the results section in this paper (especially under the Differentiation of Mordellistina convicta section).

Perhaps the Mordellistena species in our case might also be Mordellistena convicta? On BugGuide that species has been reported from inside galls on Common Ragweed, Ambrosia artemisifolia, so maybe it could also bore into galls on Common Mugwort, a plant which is somewhat closely related?

I asked @borisb, a beetle expert, what he thought about this beetle, and Boris commented, "What you have resembles those WE [in Europe] have in ragwort (Mordellistena weisei-group), though ours do not produce galls." I am assuming that Boris means that this group of Mordellistena beetles in Europe bore into the stems of Ragwort plants (does Boris mean the plant Jacobaea vulgaris?), but that they do not cause galls to form. I explained to Boris that we assume that the Mordellistena beetles here do not actually cause the galls in the Common Mugwort, but instead they take advantage of galls already created by a gall-forming fly.

And incidentally, here is a 2008 paper about differentiating the larvae of that European group of Mordellistena beetles:

@megachile made an entry in the excellent database (a great new resource from @megachile and @jeffdc) for this still currently unknown stem gall:


Posted on May 20, 2021 08:55 PM by susanhewitt susanhewitt | 35 comments | Leave a comment