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Wasp or Beetle? – the Redheaded Ashborer

8 Apr
A wasp-mimicking cerambycid beetle (College Station, Texas).

A wasp-mimicking cerambycid beetle, the redheaded ash borer (Neoclytus acuminatus).

Here’s an interesting long-horned beetle I found poking around in the leaf litter by my front door this week.  With its long hind legs and elongate, red and yellow striped body, this beetle resembles a wasp, and the illusion is particularly effective in motion, whether in flight or moving quickly along the ground.  Beetles like this have fooled me many times, well enough that to make me keep my distance, at least until I can take a closer look at what’s in my net.

Like other long-horned beetles (family Cerambycidae) the larvae of these beetles burrow in dead and dying hardwood trees and logs.  Because they can attack sickly or weakened trees they are a pest in nurseries.

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.

Casebearers

22 Oct
A case-bearing leaf beetle laravae (Chrysomelidae: Cryptocephalinae)

A case-bearing leaf beetle laravae (Chrysomelidae: Cryptocephalinae)

Anyone noticing one of these small brown objects on a leaf could easily dismiss it as bird droppings.  Only a close look will reveal their secret–these cases house hungry beetle larvae, who can munch on the leaf in the security of their protection and disguise.  For my own part I only discovered these insects when I took a closer look at some of the contents of my sweep net.  They seem to be relatively common in Texas in the late spring as I turned them up frequently at a number of field sites.

These insects are a type of leaf beetle (family Chrysomelidae), belonging to the sub-family Cryptocephalinae (literally “hidden head”), the case-bearing leaf beetles, or casebearers.  (For those not up to date with Latin naming conventions, the “-dae” suffix is used to indicated families, and the “-nae” suffix is used for subfamilies.)  The ‘case’ is a gift provided by the mothers–they wrap the eggs in layers of fecal matter, which the larvae later add to.

Fire Ant Symbiotes – Martineziana dutertrei

18 Oct

 

Fire Ant Symbiote, Martineziana dutertrei

A fire ant symbiote, Martineziana dutertrei, with host species.

 

Here’s another cohabitant I frequently turn up in fire ant nests.  These tiny black beetles belong to one of the largest and most diverse beetle families, Scarabaeidae, the scarab beetles.  They fool their ant hosts by coating themselves in chemicals that cause them to smell and taste like ants.  When I went to research more information on these interesting little beetles I could find very few scientific studies addressing them.  These beetles, Martineziana dutertrei, seem to function primarily as parasites of the ant colonies that host them, stealing prey and other nutrients, and even eating ant larvae.

 

An ectosymbiotic scarab beetle with a member of its fire ant host species.

An ectosymbiotic scarab beetle with a member of its fire ant host species.

 

Martineziana dutertrei was apparently introduced to the United States at some point during the introduction of its host species, either the red imported fire ant, Solenopsis invicta, or the black imported fire ant, Solenopsis richteri.  This beetle species are now also found in the nests of a native relative of the infamous imported fire ants, the tropical fire ant Solenopsis geminata, where the beetles have evidently somewhat displaced their own native relative.

 

A myrmecophilous scarab beetle with its fire ant host species.

A myrmecophilous scarab beetle with its fire ant host species.

 

 

A myrmecophilous scarab beetle in fire ant brood pile.

A myrmecophilous scarab beetle in fire ant brood pile.

 

 

A fire ant symbiote, Martineziana dutertrei

A fire ant symbiote, Martineziana dutertrei, with host species.

 

 

Aphodiine Scarab Beetle - Martineziana dutertrei

Aphodiine Scarab Beetle - Martineziana dutertrei

 

 

Aphodiine Scarab Beetle - Martineziana dutertrei

Aphodiine Scarab Beetle - Martineziana dutertrei

 

Reference: Wojcik, et al.  Ins. Soc. 38:273-281 (1991)

Cute Bug? Ladybug Life Stages

29 Sep
Ladybug on a leaf (Coccinellidae)

Cute ladybug on a leaf (Coccinellidae).

This is a special retroactive emergency update post in honor of my mother’s birthday.  Apparently I don’t post enough ‘cute’ bug pictures.  (I think they’re all cute, but that’s just me.)  Ladybugs have been demanded and will be supplied.

Pupa of a ladybug.

Pupa of a ladybug.

This is a somewhat less cute picture of a ladybug pupa.  This is the ladybug equivalent of a chrysalis or cocoon.  It is an inactive, resting life stage while the ladybug restructures its body into it’s adult form.  The ladybug’s aposematic coloration which warns that it is toxic to eat allows it to pupate exposed on the leaves of plants in the midst of its primary food source–aphids.  Many other beetles pupate underground, inside plants, or drop to the leaf litter at the base of trees to pupate.

Cannibal ladybug larva (Coccinellidae).

Cannibal ladybug larva.

And finally a picture of a ‘baby’ ladybug.  Awwww.  I had to look closely to figure out what was going on in this picture.  At first I thought it was a ladybug larva molting out of its previous skin, but in fact this larva is apparently cannibalizing another ladybug larva.  Delicious!

Happy birthday, Mom!

In a Name – lady beetles and insect naming

12 Jul
Ladybug

Ladybug in the leaves.

Here’s the familiar adult form of the strange little guys from the last post.  These are commonly known as lady beetles, ladybugs, and sometimes even ladybirds.  Ever wondered about the difference between ‘ladybug’ and ‘lady beetle’? (Too bad, I’m telling you anyway!)

Here’s an interesting little trick I learned for figuring out the correct spelling for those weird mix-up common names that pop up frequently in insects (and other groups!).

If the insect name contains a word that describes a group it is actually part of, that word can stand alone.  So, in the case of the beetle above, we get ‘lady beetle.’  Another good example of this would be ‘horse fly,’ which is, in fact, a type of fly. (But not a type of horse.)

If the insect name contains a word that describes a group it not actually part of, the words are run together.  So, we have ‘ladybug’ and ‘ladybird.’  Most people will have no problem remembering that a ladybird is not actually any type of bird.  The ‘bug’ question may seem a bit more confusing, but remember ‘true bugs’ belong to the familyHemiptera.  Beetles are not ‘true bugs.’  Thus, ‘ladybug,’ all one word.  Other good examples of this are ‘butterfly‘ and ‘dragonfly,‘ neither of which are flies.

What’s the point of this?  Well, you can hazard a good guess that armyworms and silkworms aren’t actually worms. In fact, they are both types of caterpillar (butterfly larvae).  Similarly glowworms is a widely used common name for a number of insect larvae, including those of fireflies.  For that matter fireflies aren’t flies–they’re beetles!

Don’t get carried away, however.  While yellow jackets are not actually jackets, it is perfectly acceptable to leave the space. (A yellow jacket jacket would be uncomfortable.)

Minute Monster – the immature ladybug

9 Jul
Baby ladybugs!

Baby lady beetles munching aphids.

Another picture from right in my backyard!  Unlike their pretty and popular adult form, ladybug larvae look a bit like they ought to be featuring as monsters in a horror movie, and they are indeed fearsome predators.  (At least of the very tiny.)  But just like grown up ladybugs these strange critters are the gardener’s friend, since their favorite prey are aphids.  Another trait they have in common with adult lady beetles is their bright coloration.  This aposematic, or warning, coloration serves to alert predators that they are not good to eat, due to the toxic chemicals they sequester in their bodies.

Lady beetles belong to the family Coccinellidae, which takes it name from the word coccus, meaning circular, due to the adult beetle’s nearly circular shape.  They are also generally almost flat on the bottom, allowing them to draw their legs under their armored exoskeleton and fit almost perfectly against a plant surface when under attack.

Pretty Plumes

18 Jun
Larvae on leaf.

Gregarious insect larvae eating a leaf in Argentina.

These little guys were tiny enough to overlook easily, but bizarre and striking on close inspection.  I am informed that the peacock like ‘plumes’ on the ends of these insects are likely to be made from cast skins or even ‘tubes’ of excrement.  The beauty of nature.

A leaf-skeletonizing chrysomelid larva on an arm.

A chrysomelid larva on an arm.

Insect larvae can be tricky to identify, but general consensus among entomologists I showed this to, is that these are some sort of chrysomelid (leaf beetle) larvae.  The family Chrysomelidae is a large and diverse group of small to medium sized beetles which take on a variety of forms, but tend to be found feeding on plants in both the larval and adult forms.  These particular larvae appear likely to be skeletonizing leaf beetles*, so named from the manner in which they feed off the plant, and the leaf ‘skeleton’ left behind.  Like many insect larvae, these appear to be somewhat gregarious, as I observed them mostly in small groups.

Two tortoise beetle larvae (Cassidinae) with dimorphic coloration.

Two chrysomelid larvae with dimorphic coloration.

*Update:  Laura suggests that these should be Cassidinae, or the larvae of tortoise beetles (see comments).  Tortoise beetles are fabulous little critters, so I’m thrilled to learn that their babies frequently make dramatic poop structures.