A good home for the Hackberry Emperor

Asterocampa celtis, Hackberry Emperor

It seems I've unintentionally laid out the welcome mat for this season's Hackberry Emperors. I've been seeing them flash around my yard in ones and twos for the past week or so. They have a very jerky, quick style of flight. Sometimes they alight on trees and shrubs. That's how I was finally able to take a picture to get an ID.

The Hackberry Emperor's species epithet "celtis" refers to their preference for the hackberry tree, Celtis occidentalis. Their larvae only eat the leaves of trees in this genus. The adults, however, eat dung and rotting fruit. I happen to have a dog who produces abundant dung and a peach tree in my backyard, and  a couple hackberries on my property.  I really threw a party for them. No wonder I've seen them all over the place.

Now that I've got a picture and put a name to this butterfly, it's the caterpillar I'm after. Hackberry emperor adults are perfectly charming, if a little drab. Their caterpillars are spectacular. Their heads are framed by a shield of spikes and they have two spiked tails on their rump. You can find pictures here and here.

Hackberry emperor caterpillars hide themselves in folded leaves during the day and come out at night to feed. Supposedly shining flashlights up into the canopy after dark is a good way to spot them. I'd love to get a look at these fantastical caterpillars, so I may very well try.

Mothing at Cedar Ridge Preserve

Synchlora frondaria, the Southern Emerald Moth

If you are a lazy naturalist, mothing is a beautiful thing. You spread a drop cloth, turn on a light, and wait for the critters to come to you. You almost never come up empty. On Friday, the Audubon's Cedar Ridge Preserve (Dallas, TX) hosted a "Mothing" in honor of National Moth Week.

I spent the entire week studying up in anticipation. I'd never been mothing before. While I know a fair bit about native bees and a little about butterflies, I was basically ignorant on moth matters. The most useful book I found was "Peterson's Field Guide to Moths of Northeastern North America" (2012). Despite not being regionally appropriate, the pictures are fantastic and this book has a good shot of getting you to genus. From there, internet resources like www.bugguide.net and www.discoverlife.org can get you to species. I noted that many of the seasoned moth-ers brought their own copies to the event.

Moth ID can be a little daunting- there are approximately ten times as many species of moths as there are butterflies (160,000 vs 17,500). However, unlike native bees, you don't typically need a scope to confirm species. I was able to make some reasonable guesses from my photographs alone.

Petrophila bifascialis, aka the 'golden spangle-fanny'

One of my favorite moths was what we jokingly called the "golden spangle-fanny" aka, Petrophila bifascialis. They are quite ornate, and look like they have been dotted with gold leaf. They are also tiny. Three of them could land on a nickel without touching wingtips. Their second set of antennae are actually labial palps, used to identify food. Interestingly, these moths have aquatic larvae. Their young eat algae.

My other favorites were the "Emeralds" in the Geometrid family. As the name suggests, they were a beautiful green. Only the males have the lovely double-combed ('bi-pectinate') antennae. They use their extra fringe to sniff out female pheromones. We saw two different species of emerald, the wavy-lined (Synchlora aerata) and the southern (Synchlora frondaria).  The southern has more jagged white bands crossing the fore- and hind-wings, and the wavy-lined is a little bigger. Both are smaller than a dime.

Synchlora aerata, the wavy-lined emerald (possibly)

 

Synchlora frondaria, southern emerald moth

I've included more pictures, IDs, and a mystery moth after the jump. 

Handling the annual plague of locusts

Taking a rest from general wickedness

Late summer is harvest time for many of us.  Squash, tomatoes, and watermelons are ripe, sweet corn is almost ready, and baby winter squash are growing on the vine. Untended herbs like basil and cilantro are bolting, and they provide a little extra nourishment for the beneficial insects that call our gardens home. However, the dog days of summer can mean another thing to those of us in western states: grasshoppers.

Texas and much of the west seem to be inundated by grasshoppers every summer.  At least as far back as 1946 it was recorded that in July, when the temperatures hit triple digits and flowers cease blooming, a plague of grasshoppers descend¹. I decided to look into organic control options after losing my entire sweet corn and bean crops to grasshoppers this year.

What causes the outbreaks of these voracious hordes? Well, first, we removed most of their predators. Foxes, coyotes, and other small and medium sized mammals find grasshoppers delicious. Birds, spiders, and blister beetles also treat grasshopper as a delicacy. If your garden, like mine, is a small patch in an urban area you may lack the natural predation necessary to keep grasshoppers under control.  Additionally, warm, dry conditions are excellent for grasshopper development- this is why their populations tend to explode during the hottest part of the summer. Extended periods of cool, wet weather suppress their development.

Grasshoppers are not easy to control. If you’ve ever walked through a heavily infested pasture and seen them flinging themselves wildly in all directions, you recognize that they are highly mobile creatures. Because keeping them out of your garden is a largely futile task, you could consider changing your cultural practices. Corn and beans are highly preferred by grasshoppers, while tomatoes and squash are avoided. If, like me, you are unwilling to pass on sweet corn, you could consider timing your planting to avoid grasshopper season.

One of my favorite ideas for grasshopper control is to use domesticated versions of their natural predators: chickens. A number of gardeners have experimented with building ‘chicken moats’ around their gardens. Your chickens get a little extra nutrition, and your crops are spared! For those of us without backyard chickens, coating your crops with kaolin clay, neem and soapy water all have variable efficacy and are worth a shot. Loose fabric barriers around your crops can also provide some relief. Lastly, a ‘trap crop’ of unmown grass may lure the local grasshopper population away from your vegetables. Good luck, and happy gardening!

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¹Dyksterhuis, Edsko Jerry. "The vegetation of the Fort Worth prairie." Ecological Monographs 16.1 (1946): 2-29.

paper wasp observation nest

Foundress-queen and her smaller worker daughters.

A paper wasp foundress, probably Polistes exclamens, just started a new colony in one of my kitchen windows. I'm pleased to have this chance for easy observation of how these wasps live their lives-- kind of like those demonstration bee hives with glass panes. It does seem awful late in the season to be getting started. When I first noticed the nest it was just a couple foundresses and workers. Now it appears that they have successfully reared young, but no males are present yet. According to Bug Eric, males have black on their heads and thorax. I'll keep an eye out.

I did a little research, and sometimes late season colonies are 'satellite nests'. A queen may found multiple nests as insurance against total reproductive failure in the case of predation. Birds will knock down paper wasp colonies, and having extra nests insures that the queen doesn't lose her entire reproductive effort.

Unlike honeybees, paper wasp queens continue to forage and defend their nest even after the foundation of their colony. They don't specialize in baby-making to the exclusion of all other activities. Because queens take an active role in rearing their brood, there is high queen mortality. Perhaps as an adaptation to this, all female paper wasps are capable of reproduction. Workers eschew reproduction not because they are unable to do so, but because it is not their 'job' in the colony. If the queen should pass, the next-in-line, generally the eldest, assumes the role of queen.

Also unlike honeybees, only fertile queens overwinter. Workers have brief lifespans of only a few weeks, and males are only present part of the season. Fun fact: no male Hymenoptera sting. A stinger is a modified ovipositor, and males never had one.

These paper wasps are probably eating soft bodied insects, especially caterpillars. A couple of yards from the satellite nest a Hackberry tree is suffering an outbreak of webworm caterpillars. I've got to imagine the foundress noticed these tasty morsels when she was choosing where to start a new colony.

One last thing: I love bees, but I have a more complicated relationship with wasps. I've been stung by yellow jackets enough times to harbor a general mistrust for the family. However, all these wasps did when I clunked my camera against the glass was freeze in the alert position over their young. Pretty chill, really. Knowledge tends to conquer fear, so perhaps watching this family over the remainder of the summer will change my mind.

Rain lilies and botanical terminology

Cooperia drummondii, evening rain lily

I learned a new word last week. I was reading a study on watermelon pollination where an author had tracked the timing of a potential pollinator's floral visits versus the receptivity of the plant. Watermelons have male and female flowers and are entirely dependent upon insects for pollination. Their flowers are only open for part of one day-- early morning to early afternoon. On top of all this, visits to male flowers are only effective for pollen collection after anther dehiscence; that is, after the anther splits along its seam and releases pollen grains. If ever a plant had all its eggs in one basket, the watermelon is it. No un-assisted selfing or wind pollination for this species.

Rain lilies open along three seams to release their seeds

Dehiscence doesn't only refer to anthers. It is the proper botanical term for any 'intentional' release of material upon the splitting of a seam.  In the picture at left, you can see a rain lily  beginning to dehisce and release its seeds.

I've mentioned rain lilies in this blog before, and they may be my favorite wildflower I see around my neighborhood. I like the way they pop through lawns like mushrooms after a heavy rain. Their  expedited growth seems to allow them to persist in mown areas. They flower so quickly that if someone skips mowing for a week they can bloom and set seed.

We got good rains this spring/early summer in Fort Worth, so it seems to be a good year for rain lilies.    I'm collecting as many seeds as I can. I'm going to scatter them in my lawn, especially in any areas where the grass is thin. Goodness knows I'm negligent enough with my yard work that they should thrive. 

Evening rain lily (Cooperia drummondii) is more common in this area than the hill country rain lily (Cooperia pedunculata), but I've found both. C. pedunculata has bigger flowers and a 'peduncle', a distinguished flower stem attached to the main stem. The hill country rain lilies I've seen may be someone's garden escapees. 

C. pedunculata on the left, C. drummondii on the right.
Peduncle circled in red.

Cooperia drummondii seed heads in situ

Most of the seed heads aren't quite ripe yet. Ideally the seed head will be dried like paper before you harvest. My problem is that the seed heads tend to split (i.e., dehisce) almost immediately upon ripeness. I'm not quick enough to pick them. I'm experimenting with picking some a little early to see if the seeds are viable.  I tested the seeds, and they are black and doughy. I'm hopeful. Another tactic to try is bagging the seed heads prior to dehiscence. Seed collectors sometimes do this for milkweeds. When the seed head splits, instead of being scattered in the wind, the seeds are captured in a collection bag.

Another thing to consider: many ephemeral species do best when seeded immediately after flowering (unlike the majority of perennial seeds which favor dormant season seeding). I'm going to toss some seeds out now and sow others in late fall. I'll have to remember where I did what so I can learn which works best for these lilies! 

Bees on Corn

Melissodes bimaculata collecting corn pollen

Maricopa corn, image from Native Seeds/SEARCH

This year I experimented with growing my own sweet corn for the first time. I bought a multi-colored 'Maricopa' cultivar from Native Seeds/SEARCH- they no longer have it available in their online store, but it's a very popular product so I'm sure they'll restock in the fall. Native Seeds/SEARCH is a Tucson-based non-profit that specializes in North American vegetable seeds locally adapted to the southwest. I went to them for my corn, beans, tomatoes, and squash this year because I figured if it can handle Arizona, it can deal with the Texas drought. In addition to preserving these native varietals of common garden crops, Native Seeds/SEARCH also donates seed to tribes that have lost their cultural food ways.  At any rate, it's a neat project, and I've had a remarkably trouble-free garden this year. Even my little corn patch is going gangbusters.

Another M. bimaculata, hard at work.

This morning I was watering my garden, and I noticed something quite unexpected: the Melissodes bimaculata that had been so busy pollinating my squash were now collecting pollen from my corn! As most people are aware, corn is wind pollinated, so it certainly doesn't require the services of our native bees. That said, the native bees aren't hurting anything and they are doing remarkable work increasing my squash yields. Anything that keeps them healthy increases the productivity of my garden.

So: why do I care that my neighbor-bees are eating corn pollen? Well, I've heard the argument that corn pre-treated with pesticides (i.e., neonicitonoids) is harmless because corn isn't insect pollinated. After watching the bees in my garden, I feel pretty safe making the statement that there is still a high potential for exposure.

I also worry that these fuzzy little bees are exploiting the corn pollen because there isn't much else available. I know the local bee populations took a real hit when the vacant-lot prairie was scraped clear to the bed-rock. I hope they are eating the corn pollen because it's convenient, and not because they are starving!

M. bimaculata are named for their two white spots, one on either side of their abdomen