Tag Archives: biology

Insects in the vegetable garden

Here are some photographs I took in June at my allotment in town.

Spotted cucumber beetle (Diabrotica undecimpunctata howardi)

First up is a spotted cucumber beetle (Diabrotica undecimpunctata howardi), perhaps the most common insect in my garden every year. In addition to being defoliators, the beetles are important transmitters of the Erwinia tracheiphila, which causes wilting. I think some of my zucchini fruits might be suffering from this wilt, but I’m not positive. The insect can also eat corn roots during their larval phase (hence its other common name, southern corn rootworm). If any of my corn plants lodge (fall over) I’m going to attempt to find and photograph the little bastards. For a beetle with “cucumber” in the common name it’s stunning how many different types of plants this insect can survive on (per one estimate, over 40 different families). More information on the species can be found at BugGuide.

Mexican bean beetle (Epilachna varivestis)

This is a Mexican bean beetle (Epilachna varivestis) next to some of the damage it presumably caused. If you provoke them they apparently “reflex bleed”, and the blood is laced with a toxic alkaloid (Eisner et al. 1986). I haven’t yet seen their larvae (here‘s an excellent pic) but those have a different alkaloid in their glandular hairs (Attygalle et al. 1993). BugGuide has information on identification, distribution, and life cycle.

Phyllotreta striolata

This is some sort of Phyllotreta, I think, on radish. I spent several hours online trying to identify it to species but got stuck with three options that all are rather similar: Phyllotreta striolata, Phyllotreta zimmermanni, and Phyllotreta liebecki (links go to respective BugGuide pages). But the first option seems the best: “Antennae black, basal 3 segments yellow-brown, 5th segment usually 1/3 longer than 4th, its width 1/4 its length” (BugGuide). Here‘s the iNaturalist observation in the event that an expert is reading this and can help with an ID. These beetles sequester the glucosinolates of their cruciferous hosts (Beran et al. 2014).

Potato stalk borer (Trichobaris trinotata)

This weevil is Trichobaris trinotata, the potato stalk borer. The larvae get inside the stems courtesy of small notches that the female chews prior to oviposition. If any of my potatoes, eggplants, or tomatillo begins to wilt I’m going to dissect the stem in search of the larvae (I’m easily entertained). Adults are easy to ID because of their all-black head and presence of three black spots in between the thorax and elytra. More information is available on BugGuide.

Eggplant flea beetles (Epitrix fuscula)

This is one of hundreds of eggplant flea beetles (Epitrix fuscula) in my garden. In addition to defoliating my eggplants every year they are extremely small and thus hard to photograph and identify. And apparently they might be eating my beets, too, as larvae. BugGuide has cursory information on identification but for more extenstive treatments plus excellent photographs see Deczynski 2014 and Deczynski 2016.

Epitrix brevis

Epitrix brevis is even smaller than the eggplant flea beetle, above, and thus really at the limit of my camera gear and patience. They are all over my tomatillo, slowly skeletonizing some of the leaves through hundreds of tiny excavations like the one in the background of this photograph. Pestiferous, but also rather cute due to their small size. BugGuide has a page on the species but doesn’t have any interesting information. Likely too small.

Lady beetle larvae

These are the larvae of some sort of coccinellid (lady beetle), still hanging around their eggs and perhaps entertaining themselves by eating each other, as one does. I’m wondering whether they might be Harmonia axyridis (Asian lady beetle), an introduced beetle so common that is often a good guess. I need to go back and check on this location (on pole bean leaf) to find later instars or adults. Here’s my iNaturalist observation.

Clouded plant bug (Neurocolpus nubilus)

This menacing insect is a clouded plant bug (Neurocolpus nubilus) and I’ve seen several on my borlotti beans. In perhaps related news, several of my borlotti beans suddenly died this week (early July) and I’m wondering whether this bug is responsible. It’s a known pest of cotton but I can’t find any evidence in the literature that it eats legumes. More details on BugGuide.

Broad-headed sharpshooter (Oncometopia orbona)

This gorgeous leafhopper is a female broad-headed sharpshooter (Oncometopia orbona). Those white spots are chalky deposits (brochosomes) that are often found on females. Females use the substance to coat their eggs, though I’m not sure whether she uses the material from those spots. For the life of me I cannot locate a photograph of eggs protected by this chalk. I gather both males and females of this species (and other leafhoppers and planthoppers) also “anoint” themselves with this goop after each molt to better protect themselves from the elements and from sticky substances (Rakitov 1996). They are really hard to photograph because when they sense your proximity they will quickly move to the other side of the leaf. More on BugGuide.

Swift feather-legged fly (Trichopoda pennipes)

This is a swift feather-legged fly (Trichopoda pennipes), one of my favorite dipterans. I love it because (1) it’s beautiful, (2) not easily spooked, and (3) is a highly motivated parasitoid of squash bugs. I’ve never seen it in action, but they slap eggs right onto squash bugs (and several related bugs), and they do this all day long, sometimes effectively controlling the pest without any need for pesticides. They are so common that if you scroll through pics of squash bugs you’ll see the fly’s eggs regularly (e.g.). Here‘s a nice summary of its life cycle by Susan Mahr (University of Wisconsin). BugGuide.

Condylostylus caudatus

This is a male Condylostylus in the sipho group. My garden has thousands of these flies, all of them likely eating the aphids and other small insects that are present in large numbers. They are extremely skittish and hard to photograph. To make things worse, they also take flight when they detect a flash pulse, so 90% of my shots have only a leg or two. Here’s the iNaturalist observation in case you can help me with the identification. Caleb Scholtens has an excellent guide to the Condylostylus groups on iNaturalist .

Squash vine borer moth (Melittia cucurbitae)

Finally, here’s an early-instar larva of a squash vine borer moth (Melittia cucurbitae) inside a zucchini stem. I found it by examining leaf stems for surface damage caused by oviposition and early feeding by the larva (see pic #3 on my Inaturalist observation to see the damage). These are horrible pests of zucchini and yellow squash, so I tend to wrap the bases of my plants in tinfoil, plus patrol the leaves and fruit stalks for larval damage. The adult, by the way, is stunningly beautiful. BugGuide has identification help, which I recommend checking just to be sure it’s not Melittia calabaza, which looks very similar.

Finally, here’s a non-macro photograph that shows where all these insects are spending their lives, my little allotment at the Scott Arboretum Community Gardens.

Allotment at community vegetable garden

All of the above photographs, plus thousands more, are at https://colinpurrington.smugmug.com.

Nature pics from Zolfo Springs

Photographs from a week in Zolfo Springs, Florida. In case you’re wondering, the namesake spring was capped with concrete in 1960s, and the large pool it fed has been filled with dirt. But still plenty of nature to photograph.

Cuban tree frog (Osteopilus septentrionalis) on a post

Cuban tree frog (Osteopilus septentrionalis). Apparently arrived in Key West in 1931 or earlier. They eat each other as well as any of the native tree frogs, which is likely why native tree frogs are becoming so rare in the area. Reported to take up residence in bird boxes, too, which is thought to annoy birds and result in their declines. Also fond of hiding in boxes that house electrical components, which doesn’t end well. And they clog toilets. I could go on. All considered, a really awful species for Florida. And it’s spreading to other states.

Juvenile Cuban tree frog (Osteopilus septentrionalis) on lemongrass

Juvenile Cuban tree frog (Osteopilus septentrionalis) resting on a lemongrass leaf. Yes, cute, but don’t be fooled.

Black-tailed red sheetweb spider (Florinda coccinea)

Black-tailed red sheetweb spider (Florinda coccinea) with morning dew. I wonder whether the red color evolved to lure prey, perhaps mimicking a fruit or flower. Would be interesting to compare capture data with similar sheetweavers that have black bodies.

Condylostylus mundus

A male Condylostylus mundus. Longlegged flies (Dolichopodidae) are hard to photograph and ID, but I got lucky here. There just aren’t that many that are blue and chunky like this. Females of this species are green.

Copulating pair of common lovebugs (Plecia nearctica)

Copulating pair of common lovebugs (Plecia nearctica). Probably the most photographed fly on the planet. So definitely had to take one more. In addition to mating, they are fond of hanging out in large numbers on freshly painted surfaces. I have no idea why.

Geranomyia virescens (possibly)

Possibly Geranomyia virescens, a crane fly. The long proboscis is for drinking nectar, not sucking blood. It’s just a harmless pollinator.

Black stink bug (Proxys punctulatus)

Black stink bug (Proxys punctulatus). Here’s the BugGuide info page. The University of Florida has a very nice description of the species, too. Like many insects it’s gone through a half-dozen different Latin names, which makes it hard to locate interesting natural history tidbits that are often only available in old books and journals.

Hyalymenus sp. feeding on scarlet sesbane (Sesbania punicea) fruit

Hyalymenus sp. feeding on a scarlet sesbane (Sesbania punicea) pod. BugGuide says there are three species in Florida but offers no help in distinguishing them. Per some experts it could be the case that all three species are variants of a single species. If you know the answer, please leave a comment on the post or go directly to one of the iNaturalist observations I’ve made.

Yellow ants (Monomorium floricola) on cow skull

Yellow ants (Monomorium floricola) on a cow tooth. This species likes to nest in arboreal cavities so this is a fitting location. If you’d like to see closeups, antwiki has them.

Conura sp. on tomato leaf

Conura sp. (Chalcididae) on tomato leaf. I have no idea which species. And there are a lot in Florida.

Chelonus sp.

Chelonus sp. They’d land for approximately 1 second, then launch themselves for more hovering. So super hard to get a decent photograph. An odd-looking wasp because the abdomen is almost completely smooth due to fused tergites. Using wing venation alone this appears to be Chelonus kellieae (per figure in Marsh 1979), but that’s a species from Costa Rica and I’m not sure it’s in the United States. But I bet it is; its primary host, the potato tube moth (Phthorimaea operculella), is found in Florida. There were thousands of these wasps hovering over the lawn in the morning, so they are certainly eating something that’s in great abundance. They are egg-larval parasitoids (the egg is deposited into the host egg but doesn’t kill the host at that point).

Polistes bellicosus at nest

Polistes bellicosus nest. You can see an egg in the top left cell. They were not happy with me being so close. It was mutual.

New World banded Thynnid wasp (Myzinum sp.)

New World banded Thynnid wasp (Myzinum sp.). I think this is Myzinum maculatum because it has clear wings with brown tips; plus coloration and banding matches that of individuals ID’d as such (e.g.). Also, one source says the species has a cleft front claw (figure 7), and I think that’s the case here. You can tell this is a male by the curved pseudostinger at tip of abdomen. The larvae are parasitoids of scarab beetle larvae.

White-footed leafcutter bee (Megachile albitarsis)

White-footed leafcutter bee (Megachile albitarsis) resting with a section of leaf cut out of air potato (Dioscorea bulbifera). It’s one of thousands of species described by Ezra Townsend Cresson, a guy now long dead but who lived five blocks from me in Swarthmore, PA. I’ve even been to his garden several times.

Twice-stabbed lady beetle (Genus Chilocorus sp.)

Twice-stabbed lady beetle (Chilocorus sp.). Given size of spots I’m wondering whether this might be a cactus lady beetle (Chilocorus cacti). But Chilocorus stigma is super common in Florida and is said to have larger spots in the south, so I’m unsure. I should have taken a photograph of the ventral side. One of life’s regrets. They eat scale insects.

Eudiagogus maryae on scarlet sesbane (Sesbania punicea)

Eudiagogus maryae on scarlet sesbane (Sesbania punicea). Members of the genus are known as Sesbania clown weevils, appropriately. The larvae eat Sesbania, too.

Immature Surinam cockroach (Pycnoscelus surinamensis)

Immature Surinam cockroach (Pycnoscelus surinamensis). Parthenogenetic, apparently.

Assembly moth (Samea ecclesialis) on fern frond. Zolfo Springs, FL.

Assembly moth (Samea ecclesialis) on fern frond. Also called the stained-glass moth (hence the species name, I assume). Larvae eat Mexican clover (Richardia brasiliensis) but perhaps other plants as well (very little information available for such a common moth).

Eggplant webworm (Rhectocraspeda periusalis) on tomato

Eggplant webworm (Rhectocraspeda periusalis) on tomato. I spent a whole day identifying this. I’d assumed that any pest of tomato would be easy to identify, but I guess it’s rare to find it on tomato.

Graylet moth (Hyperstrotia sp.) larva on scarlet Sesbania (Sesbania punicea)

Graylet moth (Hyperstrotia sp.) larva on scarlet Sesbania (Sesbania punicea). ID is very tentative, however, and is just based on visual matches to similar caterpillars on BugGuide and in Wagner’s book. Here’s the iNaturalist observation.

Caterpillar of pale-edged Selenisa (Selenisa sueroides) on scarlet sesbane (Sesbania punicea)

For once, a caterpillar that was easy to identify: pale-edged Selenisa (Selenisa sueroides), on scarlet sesbane (Sesbania punicea). In searching for interesting natural history on this species I stumbled onto a paper by Bushwein et al. (1989) describing the larvae’s habit of chewing through flexible PVC tubing in citrus grove irrigation in search of a good place to pupate. The larvae even sealed off the holes they’d chewed, so I guess it was a good place. The authors estimated that some of the larvae travelled almost 5 meters to find such sites, which is pretty impressive. Anyway, if you have PVC irrigation in your citrus grove, make sure to get rid of suitable (Fabaceous) host plants.

Caterpillar of Brazilian skipper (Calpodes ethlius) on canna lily (Canna sp.)

Caterpillar of Brazilian skipper (Calpodes ethlius) in the process of constructing its leaf-fold retreat on a canna lily (Canna sp.). Here’s a closeup of an older larva (after I separated the leaf folds). The BugGuide information page says that the larvae can forcefully eject frass, perhaps as predator deterrent. Always a nice trick.

Larva of yellow-vested moth (Rectiostoma xanthobasis)

Larva of yellow-vested moth (Rectiostoma xanthobasis) found hidden in between two oak leaves tied together with silk. Unlike many moths, the common name here is spot-on descriptive and worth a look. There’s a nice description of this species on page 47 of Marquis et al. 2019.

Caterpillar of Zarucco duskywing (Erynnis zarucco) on scarlet sesban

Caterpillar of Zarucco duskywing (Erynnis zarucco) on scarlet sesban. NB: I opened up its retreat a bit to get a photograph. Here’s the photograph before.

Caterpillar in retreat constructed on scarlet Sesbania (Sesbania punicea)

Caterpillar in retreat constructed on scarlet Sesbania (Sesbania punicea). I’m stumped by this one, however. Possibly in the Family Tortricidae. I’ve photographed it before, and both observations are on iNaturalist … in case you can help ID it. Here’s a photograph of the retreat before I opened it up. Yes, I really enjoy opening up retreats to see who’s living there; so many caterpillars go unnoticed unless you do that.

Underside of splitgill mushrooms (Schizophyllum commune)

Splitgill mushrooms (Schizophyllum commune) growing on dead tree. Common but always beautiful when hydrated.

Small ball moss (Tillandsia recurvata) on trunk of a pine tree

Small ball moss (Tillandsia recurvata) on trunk of a pine tree. It grows on everything, even on exposed power lines. Part of their trick is the silvery trichomes that capture water and funnel it into the plant.

In the unlikely event you’d like to see even more photographs from Zolfo Springs, please see my SmugMug site.