Tag Archives: larvae

Life of a carpenter ant

24 Jun
Camponotus brood - larva, pupa, cocoon

Carpenter ant pupa cocoon and first instar larvae.

Ants, like butterflies, are holometabolous and go through complete metamorphosis with an egg, a larva (~caterpillar), a pupa (~chrysalis/cocoon), and adult ant (~butterfly).  In ants, the larvae resemble small white grubs and cannot move by themselves–they are fed and tended by the worker ants.

Newly hatched ant larvae in brood pile.

Carpenter ant first instar larvae viewed under magnification.

The larvae are covered in fine hairs which help them stick together in clumps, making it easier for adult workers to move and tend them.  In fire ants, these hairs also help with rafting behavior, because they can trap a layer of oxygen around the larvae, helping them breathe and making them extra buoyant.  Rafting fire ant colonies use their babies as tiny floatation devices.  Please take a moment to consider the wonder of nature.

As they grow, the larvae molt several times, and each growth stage is referred to as an instar.  The larvae pictured above are extremely tiny because they are first instar larvae, having only recently hatched.

Inside an ant pupal cocoon.

A pupating carpenter ant larva after spinning her cocoon.

When the larvae are old enough they prepare to metamorphose into adults.  Some ants, like these carpenter ants, spin themselves into cocoons to pupate, while others, like fire ants, leave their pupae exposed.  Above, you can see an opened cocoon that contains a larvae that has not yet molted into its pupal form.

Additional fun fact: ant larvae have a closed digestive tract (I assume to prevent them from making a mess all over the colony.  It’s like the ant equivalent of diapers.). They poop for the first time when they molt into pupae.  Best line from a paper ever:  “…the larva defecates for the first time…. Workers help out.” (Taber, 2000).  This is also the least appealing job description.

An opened ant pupa cocoon.

A carpenter ant pupa in her opened cocoon.

While the job of the larva is eating and growing, the job of the pupa is developing–reorganizing its system into an adult ant.  Ant pupa look basically like unmoving, pale adult ants, darkening up right before their final molt to adulthood.  The newly molted ants are still fairly pale and soft-bodied.  They are referred to as “callows.”  Their exoskeleton darkens as it hardens, until they are prepared to go about the daily business of an adult worker ant.

Magnified camponotus ant.

Adult carpenter ant worker.

PS:  Here is a cool video of a queen ant helping a pupa shed its old larval skin.

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How to Build a Bunch of Different Formicaria

18 Apr

Since my “Ant Farms: How to Build Your Own Formicarium” page is one of my most visited articles, I’ve created a page to compile some different ant rearing/formicaria designs that I have seen or used.

Please check it out!

Acrobat ants in a flat plaster nest.

Acrobat ants in a flat plaster nest.

Carpenter ants checking out air holes at the top of the stacked colony.

Carpenter ants checking out air holes at the top of a colony.

Monomorium minimum ants in with a tube ant nest.

Monomorium ants with a tube nest.

Rover ants and queen with brood in plaster nest.

Rover ants and queen with brood in plaster nest.

See more at:

Ant Farms: More formicaria designs

and see also:

Ant Farms: How to Build Your Own Formicarium

Techniques

Fluffy Caterpillars and Latin Names

12 Apr
Spiky black yellow red white caterpillars with tussocks.

Colorful silkworm caterpillars feeding on vegetation.

These coloful and spiky fellows are silkworms of the species Apatelodes pudefacta.  The large, rather fluffy and spiky-winged adults are often mistaken for hawkmoths, and the tufted caterpillars can resemble tussock moth or dagger moth juveniles.  In fact, the genus name “Apatelodes” literally means “looks like Apatela,” a reference to the old genus name for dagger moths.  (“Apatela” later became “Acronicta.”)

This particular species gets two obscure references in its name.  The species name “pudefacta” means “ashamed” and is likely a play on the related species “diffidens” meaning “diffident.”

The moral of the story is that scientists cannot be trusted to name things in non-confusing ways.

Fuzzy black yellow red white caterpillar with tussocks

Beetles and Parental Care

15 Jun
A bess beetle and its larvae in a rotting log.

A bess beetle tends larvae in the interior of a rotting log (Photo courtesy Paul Lenhart).

A few weeks back I did a post on bess beetles, and their fascinating social structure.  These beetles live together in family groups, communicate via an elaborate vocabulary of squeaks, and cooperatively care for the developing brood.  Paul Lenhart recently snagged this awesome photo of an adult beetle with a group of larvae and was kind enough to let me share it with y’all here at 6legs. I thought I’d take the opportunity to do a bit more research and elaborate on what I learned last time.

Initially, a male or female beetle finds a rotting log, and begins hollowing out a tunnel.  Later the beetle will accept a mate, following an elaborate courtship ritual complete with specific acoustical signals.  The mated pair then cooperates on the tunnel and defends it fiercely from intruders.  A clutch of about 30 eggs is laid in a nest of finely ground wood in the tunnel.  When the eggs hatch into larvae, the parents cooperate to feed them specially prepared food–specifically wood which has been pre-chewed, passed as feces, and partially digested by microorganisms.  When the larvae pupate, the adult beetles construct protective pupal cases around them out of wood debris and feces.

Interestingly, young adult beetles cooperate with the parents to help care for their siblings.  The mated pair can have several clutches of eggs over the course of a year, and will often court and mate again in the nest when the initial brood has pupated.  Newly eclosed young adults require several weeks or even months for their adult exoskeletons to fully harden and darken to black.  These young adults are called “teneral” or “red” beetles, and remain in the tunnel, feeding larvae, helping to construct pupal cases, and defending against intruders.  Evidence suggests they may sometimes remain even after reaching full adulthood, assisting their parents and siblings.  Eventually, these beetles migrate from the log to join a mate and start their own family.

(Schuster & Schuster, 1985)

Cunning Caterpillars

13 Apr
A luna moth caterpillar with coin for scale.

A luna moth caterpillar with an Argentinean peso for scale.  For some reason this was the only coin I could find.

I wasn’t going to do another caterpillar post but I haven’t had a chance to key out the springtails for the other post I’m working on, so here you go.  As you can see, they’re still growing like fiends.  Also, I haven’t been to Argentina in two years; how is that peso still in my wallet?

A luna moth caterpillar with front half of body raised.

Yesssssss….. Exceeeeellent.

Overnight all my caterpillars turned into evil masterminds.  Or so it would appear.  Just days before they all appeared to be perfectly innocuous little caterpillars who sometimes tried to chew off their siblings’ faces.  But now just look at that caterpillar!  He’s clearly up to something.

Plotting Mr. Burns.

Someday soon I will be a beautiful butterfly.

I can’t find much in the literature on this reared-head posture–which appears to be pretty common in this family of caterpillars–but popular opinion around the internet seems to be that this is a defensive/camouflage posture to make the caterpillars look less like food to hungry predators.  They do resemble little green twigs, although it’s kind of creepy when they’re all lined up in a row staring at you.  It also puts them in a good position to employ another defensive response: clicking and puking!

A luna moth caterpillar (actias) on partially eaten leaf.

A luna moth caterpillar in feeding posture on a partially eaten leaf.

When disturbed, late instar luna caterpillars and many other bombycoids (silk moths, hawk moths, emperor moths, etc.) make an audible “clicking”, “squeaking” or “crackling” noise with their mandibles and then regurgitate noxious chemicals.  The regurgitant is apparently broadly deterrent to both vertebrate and invertebrate predators:  in the kind of science experiment I love, Brown et. al (2007) demonstrated that both ants and mice reject food treated with caterpillar puke.

I haven’t heard mine click, but they have spewed brown goop all over when I change their leaves.  I chose not to eat them, so it was apparently an effective deterrent for human predators as well.

No, Mr. Bond, I expect you to die.

>>The Luna Moth Saga

Cute, fuzzy, cannibalistic

6 Apr
Luna moth caterpillars on walnut leaves

Newly hatched caterpillars.

The luna caterpillars are still rocking along so far.  They eat like hungry hungry hippos so it’s a race to keep them well-foliated.  I’ve been making lots of trips down the street for more walnut leaves.  But how can you not love these sweet little faces?

Luna moth caterpillar close up.

Sweet little face.

Fun story:  Today when I was snipping of bits of leaves to move the caterpillars to fresh foliage I accidentally snipped one caterpillar in half.  (I did mention I’m terrible at caterpillars.)  Anyway, the two nearest  caterpillars immediately started chowing down on their dearly departed sibling like it was the best thing since bacon ice cream.  Then, apparently, they got so carried away they started trying to eat each other, and for the first time in my life I got to break up a caterpillar fight.

Luna moth caterpillar close up.

I’m fuzzy like a teddy bear!  And may also try to eat your face!

My caterpillars are a bit overcrowded at the moment, so I’m planning to spread them out across a few more containers.  On the other hand, I suspect if I don’t they’ll take care of the issue for me.

Luna actias Caterpillar on Quarter

First this quarter, next the WORLD.

>>The Luna Moth Saga

Nooooooooo (Attack of the Carpet Beetles)

9 Mar
Bee fly in insect collection with missing eyes due to carpet beetle damage.

Bee fly with eyes eaten out by dermestids.

Here’s a sight no insect collector wants to encounter in the collection boxes.  I was sorting a mixed box of pinned specimens when I found that this fuzzy bee-mimicking fly had met a second untimely fate  (the first being the fate that led him to be pinned in my collection).  As you can see, the large bulbous eyes that occupy most of the bee fly’s head are, um, no longer occupying.  In fact, they’ve been rather neatly eaten away.  Apparently, bee fly eyes are delicious.

Carpet beetle eating collection specimen (Arctiidae, Dermestidae)

Dermestid damage in an insect collection.

With mounting horror I sifted through the collection box and found all the signs: tattered insects, scattered frass, and (the smoking gun) cast off larval skins.  One hairy skin stuck to the wing of a tiger moth whose hollowed out abdomen had apparently made a tasty treat.

Cast off skin of a dermestid larva.

Cast off exoskeleton of a carpet beetle larva (Dermestidae).

Dermestids.  Oh, joy.  Is there any insect that is more unwelcome in an insect collection?  (Actually, my friend Paul had an unpleasant experience with a voracious colony of fire ants, but that’s another story.)  These guys, often called carpet beetles or hide beetles, are dietary specialists on dry, high-protein organic materials.  Everything from dandruff to leather to natural fiber carpeting may become their food source.

Dermestid close up.

Carpet beetle close up (80 times magnification).

This not only makes these beetles a damaging household pest, it makes them both dangerous and very useful to to people who work with dead things.  When they’re not uninvited guests, dermestid beetles are frequently used to “clean” skeletons, removing hide, flesh, and all.  If you’ve every watched the show Bones, you may be familiar with Zack’s colony of “flesh-eating” beetles kept for this purpose.  (Zack: You can’t kill them.  They have names.)

The scaled exoskeleton of a varied carpet beetle (Anthrenus verbasci).

The scaled exoskeleton of a varied carpet beetle (Anthrenus verbasci).

These particular guys were varied carpet beetles, a fairly common indoor pest.  Examining them under a scope reveals that these tiny, nondescript little blobs are quite striking.  The beetles are covered with tiny, multi-colored scales in orange and white and black and their rotund little bodies, with legs retracting into grooves, mak them look something like carnival balloons.  Pretty adorable for something that can leave a trail of carnage and destruction in its wake.

The legs of the dermestid beetle can tuck back into grooves.

The legs of the carpet beetle can tuck back into grooves.

Luckily, the damage was fairly limited (the two specimens pictured here were by far the worst off) so I can consider the whole incident with amusement and interest.  The pictures were fun.  The collection?  Is cycling through the freezer.  Only dead bugs welcome in these boxes.

Pinned dermestid beetle with hand for scale.

Pointed carpet beetle with hand for scale. (Thanks to Loriann Garcia for providing the pointed specimen for the impromptu photo shoot.)

A/N:

Can we talk for a minute about the fact that I took all these pictures with my cell phone?  Forget hoverboards; we are living in the futureRight now.

It would never have occurred to me to point an iPhone down a dissecting scope without Alex Wild’s recent post over at Myrmecos.  Clearly, I had tons of fun with this.  I highly recommend it.

Maggot Art Live

24 Feb

Here’s a video I put together of the “maggot art” I talked about earlier this week.  Enjoy!

 

Maggot art, etc.

20 Feb

Maggot art with Chrysoma rufifacies, the hairy maggot blow fly

Two new pages up today in the Techniques section.

I’ve started a collection of cool insect-related techniques as I happen across them around the internet:

Techniques from Around the Web

I also had a lot of fun doing maggot artwork at an outreach event and I put together a “how to” post on that.  Check it out!  The pics are all taken with my iPhone but they turned out great:

How to Paint with Maggots

Maggot art makes a nice item to sell or give away at events, and it also provides a fun, hands-on outreach opportunity that people of all ages can enjoy. It’s great to watch people go from “Ew!” to “Ooh!” as they see a disfavored insect make something pretty and interesting. Don’t forget to talk to people about the role of maggots in the ecosystem, the life cycle of flies, and the usefulness of maggots in cleaning wounds. The maggot artwork also makes for a nice souvenir to take home, and hopefully encourage people to talk about what they learned with even more people.

Life Cycle – Red-headed Chrysomela leaf beetle

22 Apr
A red-headed Chrysomela leaf beetle (Chrysomela texana).

A red-headed Chrysomela leaf beetle (Chrysomela texana).

These  red-headed Chrysomela leaf beetles were all over the park near my home this week, mostly in the vicinity of a large willow tree, the beetles’ food of choice.  Chrysomela texana are close relatives of the cottonwood leaf beetle (Chrysomela scripta).   C. texana can be easily distinguished by it’s red pronotum, head, and underside (most similar species have distinct black markings on these areas).  Every life stage of the beetle was apparent, from the yellow eggs laid in clusters on a leaf, to the lady beetle-like black and brown larvae, skeletonizing the surrounding vegetation in gregarious clusters, the red-brown pupae.

A cluster of yellow red-headed Chrysomela leaf beetle eggs on the underside of a leaf.

A cluster of yellow red-headed Chrysomela leaf beetle eggs on the underside of a leaf.

(Note: The egg hunt was successful.  Happy Easter!)

Red-headed Chrysomela leaf beetle larvae (Chrysomelidae: Chrysomela texana) skeletonize a willow leaf.

A gregarious cluster of red-headed Chrysomela leaf beetle larvae skeletonize a willow leaf.

Like swallowtail caterpillars, the larvae have cool, eversible glands which they use to secrete defensive chemicals (as pictured by Mike Quinn on BugGuide).  The pupae of these beetles were particularly abundant.  They seemed to be stuck to every surface I looked at–tucked under bark, into crevices, dangling from leaves and even from small flowers and weeds.  This gave me the chance to snap the pictures below of a beetle struggling out of its pupal case. I even took a few home, but they were sneaky and eclosed on me when I wasn’t looking.

A red-headed Chrysomela leaf beetle (Chrysomela texana) ecloses from its pupal case.

A red-headed Chrysomela leaf beetle (Chrysomela texana) ecloses from its pupal case.

A red-headed Chrysomela leaf-beetle ecloses from its pupal case (Chrysomelidae: Chrysomela texana).

A red-headed Chrysomela leaf-beetle ecloses from its pupal case.

Cast of pupal case of a red-headed Chrysomela leaf beetle (Chrysomelidae: Chrysomela texana).

Cast off pupal case of a red-headed Chrysomela leaf beetle.

*edit*

Surprise bonus image!  Now the life cycle is complete. 😉

A mating pair of red-headed Chrysomela leaf beetles (Chrysomelidae: Chrysomela texana).

A mating pair of red-headed Chrysomela leaf beetles (Chrysomela texana).