Archive | November, 2010

Mantis Montage

29 Nov
Chinese mantis first instar nymphs (Tenodera sinensis).

Chinese mantis first instar nymphs (Tenodera sinensis).

Here’s some video clips of the Chinese mantises I reared out of an egg case early this year.  I enjoyed watching them hunting fruit flies, grooming, fighting, and molting.  These are pictures of mantises in the first instar, or first molt, not long after hatching.  At this age they’re tiny and fairly vulnerable, but also fast and terrific jumpers.  I’ll include some pictures of adults in the next post.

Mantises are a lot of fun to raise as pets.  They’re low maintenance, fun to observe, and one of the more charismatic and interactive insect pets–they’ll turn their heads back and forth to watch you and even take bits of food offered with tongs.  In the spring you can find mantis egg cases (ootheca) for sale on a variety of garden websites as well as eBay.

Jumping Spider Greetings

26 Nov
A jumping spider (Salticidae) peering over a grass blade in Argentina.

A jumping spider (Salticidae) peering over a grass blade in Argentina.

I couldn’t think of any Thanksgiving related insects (poultry lice might be appropriate but I don’t have any pictures and they don’t exactly make me hungry for turkey) so instead here’s a close up of a  jumping spider from Argentina.  I figured it worked for Halloween, so why not?

This fellow’s keeping a wary eye on the camera since I had just startled him out of his refuge and chased him up and down the grass blade trying to get a shot of him.  Bugs love me.  I’ve talked about jumping spiders a couple times before so if you’re overwhelmed with a need to know more about these little guys you are in luck!    Otherwise, go eat some turkey!

Happy Thanksgiving!


22 Nov
Male scorpionfly (Mecoptera: Panorpidae)

A male scorpionfly in sedge meadow (Lick Creek Park, TX)

Entomology has radically changed my views and responses in relation to any number of subjects.  Sometimes this means that I find myself poking at bees in flowers or attempting to coerce angry wasps into tiny vials despite a former terror of these insects.  Sometimes this means I jump on a cockroach with my bare hands just because I really need one for a class collection and in spite of a lingering revulsion towards them.

And sometimes this means I find myself saying things that sound completely normal and reasonable to me only to notice that my conversational partner is now staring oddly at me.  Things like: “Hey, that’s a scorpionfly!  They’re really cool because the males have genitals shaped like a scorpion tail!”  …cue bewildered, uncomfortable silence.

But the fact remains that male scorpionflies do have genitals that resemble a scorpion’s stinger, and this is really cool.  It’s not my fault nature is weird.

Female scorpionfly (Panorpidae)

A female scorpionfly perches on a stem (Lick Creek Park, TX)

Scorpionflies are yet another insect that I had never even heard of before I started studying entomology.  And yet, like so many other insects, it turns out that once I know to look for them they’ve been under my nose all along.  Just a few weeks ago the sedge meadow area of our local Lick Creek Park was swarming with these striking insects.  Scorpionflies belong to the order Mecoptera and the family Panorpidae.  Aside from the distinctive ‘tails’ of the male scorpionflies (the females lack these), they can be distinguished by their elongate mouthparts, giving them a horse-like face.  Adults are opportunistic scavengers, feeding on nectar, dead fruit, and dead insects.

The bizarre scorpion-like genitalia of the males cannot sting, but instead function as ‘claspers’ to hold on to the female during mating.  This is actually a fairly common adaptation in male insects.  Male dragonflies, for example, use their claspers to latch onto the female’s head while mating, and many male damselflies stay latched on for some time after mating, to guard their mate from the attentions of other males.   Scorpionfly males are fairly gentlemanly about the matter, and begin courtship by offering a ‘nuptial gift’– either a dead insect or a tasty ‘salivary secretion’ in the form of a gelatinous mass.  (Valentine’s Day, anyone?)  The better the gift, the longer the female will spend eating it, and the longer the male will get to mate, resulting in more eggs fertilized and more offspring for the male.  A win for everybody.


Out with the old; In with the new! — Twig Ants

19 Nov
Twig ants (Pseudomyrmex) carrying food to the nest.

Elongate twig ants (Pseudomyrmex gracilis) carrying food to the nest.

More pictures from the Pseudomyrmex colony that nested in my window lining last spring.  The workers above posed nicely on the window glass as they all tugged on a bit of food.  Normally the workers of  Pseudomyrmex colonies tend to forage independently, relying on their speed, size, and potent sting to bring down prey and haul it back to the nest alone.  However, in this case, the haul in question apparently attracted the attention of some other workers.  People tend to think of ant colonies as perfectly synchronized machines, operating in perfect unity.  However, anyone who has actually watched a group of ants attempt to maneuver a large prey item down a small nest entrance will have noticed that it’s more like a game of tug-of-war, with hopefully most of the pieces deciding to pull in the appropriate direction.  The same sort of ‘rule-by-majority’ principle applies to any number of colony processes, such as selection of a nest site.  I have personally watched a group of acrobat ant workers purposefully hauling larvae to a new nest location, while a second group of workers diligently hauls them right back, passing each other on the way.  They’ll also drag the queen along if she doesn’t cooperate.

A twig ant worker (Pseudomyrmex) removing trash from windowsill nest.

A twig ant worker (Pseudomyrmex) removing trash from windowsill nest.

In the Life of an Ant

15 Nov
Twig ants (Pseudomyrmex) nesting in a windowsill

Elongate twig ants (Pseudomyrmex gracilis) nesting in a windowsill

Last spring I had the pleasure and entertainment of some of my favorite ants setting up camp in the exterior lining of my front window.  Pseudomyrmex is one of the groups of ants that truly displays the close relationship to wasps in their form.  I have never been stung, but I’m told it’s fairly painful.  Luckily, like many insects, they are not particularly aggressive towards humans unless truly provoked.  In general these ants responded to my getting too close with the camera by dropping off the wall to the ground, a fairly common escape behavior.  It was fun to watch the workers as they hauled home their catches and try to identify the prey item.

A twig ant (Pseudomyrmex) preys on a plant bug (Miridae).

A twig ant (Pseudomyrmex) preys on a plant bug (Miridae).

Mirids (Miridae), commonly(and rather vaguely) known as ‘plant bugs’ were all over the place at the time, and seemed to be a fairly common catch.  My personal favorite was the small critter seen below, whose large curved jaws identify it as a neuropteran larvae, one of the net-winged insects.  It’s likely a lacewing larvae, but–as a number of antlions had set up pits in the sand below the window–I am personally fond of the idea that this is a case of ant eating antlion.  Sweet revenge!

A twig ant returning to the nest with its neuropteran prey.

A twig ant returning to the nest with its neuropteran prey.

In a Pinch — the Scorpion’s Chelicerae

12 Nov
The chelicerae of a scorpion are visible as it devours a cricket.

The chelicerae of a scorpion are visible as it devours a cricket.

8legs2many today!  I found this little guy hunting near a lightsheet at the Welder Wildlife Refuge.   As a general rule of thumb smaller pincers mean a more powerful sting, so I took care handling this little guy.  Above, you can see him chowing down on a feeder cricket I gave him.

Like spiders, scorpions are arachnids, with eight pairs of walking legs.  Their large front claws are not true legs, but actually modified pedipalps, appendages on the prosoma used by chelicerate arthropods for handling food.  While snapping pictures and shooting video clips of this guy I also got a chance to get a close up look at another cool appendage– the chelicerae.  These are two sharp pincer-like mouthparts used to grab the food and tear off small pieces.  These are pulled into the preoral cavity, where food is digested externally prior to being sucked down in liquid form.  Chelicerae are unique to a subgroup of arthropods called the Chelicerata–which includes arachnids, horseshoe crabs, and a weird little group called the sea spiders.  In spiders the chelicerae bear the fangs (these were the metallic green mouthparts we saw on the bold jumping spider a few posts ago).

Scorpions actually make pretty interesting pets, needing only a warm dark environment with some kind of refuge.  Scorpions (and other arachnids) lack the cuticular layer of wax which protects insects from dessication. * It is important to maintain high humidity to prevent them from drying out, particularly for tropical species.  They are nocturnal, and so most active at night, which is the best time to feed them.  Because they are adapted to living in darkness, they are sensitive to UV light, which can harm them with prolonged exposure.  They also fluoresce vividly under a blacklight, which can be a fun way to hunt for them at night, although, again, longterm exposure should be avoided.

*Edit:  See comments below.  Thanks, Dave!

Roll With It – Dung Beetles

8 Nov
Dung beetles rolling a dung ball (Welder Wildlife Refuge, Texas).

Dung beetles rolling a dung ball (Canthon sp., Welder Wildlife Refuge, Texas).

I ran into a number of these interesting beetles flitting among the flowers and going about their business at Welder Wildlife Refuge.  I have also encountered their relatives taking care of the dog poop at the local park.  Though a bit stinky from their work, these beetles provide a valuable service to the ecosystem, cleaning up the dung dropped by large mammals.  Many dung beetles build nest directly under the dung pad, grabbing pieces and burrowing down beneath to feed in shelter.  Species like the beetles above (also called ‘tumblebugs’) secure this precious resource from competition by building a large dung ball and rolling it off to a safe burrow elsewhere.  The dung provides food for the adults and the young, which grow up safely ensconced in the burrow, feeding on the hard work of their parents.

A dung beetle with its dung ball (Welder Wildlife Refuge, Texas).

A dung beetle with its dung ball (Canthon sp., Welder Wildlife Refuge, Texas).

My favorite bit of dung beetle lore is the Australian Dung Beetle project.  When cattle were introduced to Australia they had a problem.  The native dung beetles, adapted to marsupials and the like, wouldn’t eat the cow patties.  Cow poop was piling up in the fields, and flies and worms were piling up in the cow poop.  There are more than 30 million cattle in Australia, producing more than 10 million cow pats an hour.  It was a serious, stinky problem.    Luckily, entomologist Dr. George  Bornemissza, came up with a solution, and organized the import and introduction of more than 20 species of foreign dung beetles to handle the clean up.  As another example, we have the species below, the brown dung beetle or gazelle scarab, a native of Africa and Asia. This beetle was introduced to the south eastern United States in the 1970s by the USDA to suppress harmful dung-breeding flies such as horn flies.

Dung beetles belong to the the beetle family Scarabaeidae, the scarab beetles. Lamellate antennae (branched somewhat like antlers as seen above) are diagnostic of the scarab beetles, and shovel like faces and strong burrowing forelegs help to distinguish them as dung beetles.

A male dung beetle common at lights in Texas.

A male brown dung beetle (distinguishable by the horns), or gazelle scarab, common at lights in Texas (Onthophagus gazella).

*Edit:  Thanks to Paul Lenhart for beetle IDs and additional information about the gazelle scarabs!

Tumbling Flower Beetle

5 Nov
Tumbling flower beetle on daisy (Mordellidae)

Tumbling flower beetle on daisy (Welder Wildlife Refuge, Texas).

This little beetle is a tumbling flower beetle, a member of the family Mordellidae.  Although small and easily overlooked, tumbling flower beetles can be identified relatively easily by their characteristic wedged body shape, with a humped back and pointy abdomen which extends beyond the wing case.  They are frequently black, but may also have colorful patterning.  As their name would suggest, tumbling flower beetles are generally found on flowers on which they feed as adults, although a few species also bore in dead wood.  They take their common name from their defensive behaviors.   Like many insects, when disturbed they will frequently drop from their plant perch to the ground, a maneuver which helps them avoid predators and entomologists with cameras.  They will also ‘tumble’ and gyrate about when cornered.


1 Nov
An adult mantidfly (Mantispidae)

An adult mantidfly (Mantispidae)

One of my friends collected some spider egg cases at Lick Creek Park a few weeks back and was very surprised when instead of baby spiders the mantidfly seen above emerged.  These little guys have some of the most fascinating life histories I’ve heard of.  Adult mantidflies are predatory, catching small, size appropriate insects in their raptorial forelegs.  The larvae of various mantidfly species are generally either predators or parasitoids.

Larvae of the Mantispinae sub-family employ a specially interesting strategy for predating spider eggs.  The first instar larvae are mobile, and seek out a spider egg sac to enter. Some species chew through the spider silk, but this is a tough material.  Other species get around this trouble by hitching a ride on a female spider, and actually getting themselves spun into to the egg case as the spider lays her eggs.  Once inside they spend the rest of their larval development safely ensconced, feeding on the spider eggs.  They eventually pupate and emerge as the adult mantidfly seen above.

A mantidfly strikes out with its raptorial forelegs.

A mantidfly strikes out with its raptorial forelegs.

Mantidflies, also called mantispids, mantisflies and mantid lacewings, are not actually related to preying mantises.  They belong to the family Mantispidae in the order Neuroptera, the net-winged insects such as lacewings and antlions.  Their similarity to preying mantises is a striking example of convergent evolution–when unrelated organisms faced with a similar ecological challenge independently evolve a similar biological trait.  Another good example of this is the case of dolphins and sharks with their similar streamlined bodies and fins, or even bats and birds with their wings for flight.  Both preying mantises and mantidflies are predators, and their large raptorial forelegs give them a long reach and a firm hold for a quick snatching of prey.

A mantidfly perches on a finger.

A mantidfly perches on a finger.