The Twelfth Course

Sagehen1Hello my dear blog readers.  It has been quite a long time since last we spoke.  I have no grande excuse except perhaps the grandest of all – being a graduate student.  These last few months have been a whirlwind of activities, events, and to-dos.  Many things have transgressed and life lately has been like cooking a twelve-course meal.  This little blog has been on the menu the whole time, but it’s been sitting on that very, very back burner – simmering, oh so slowly.

After being away from writing here for so long, I’m finding it difficult to jump back into the swing of things.  Where shall I begin?

I think it’s time to take some time and smell the wildflowers.  I was recently up at Sagehen Field Station and the wildflowers were blooming everywhere.  There is something so magical about sitting in the middle of a field of flowers in the Sierras and breathing in the mountain air.  I hope you enjoy a bit of their beauty too and I hope to be back again soon to talk about beetles.


Instagram outreach

After reading a recent blog post about the use of Instagram to engage the public in scientific research, I realized that I never shared several photographs, which happen to be fairly Instagram-esque.  These were composed for a science communication class that I participated in last semester and the concept was to have an art exhibit depicting some general science concept.  I chose sexual dimorphism and its many manifestations in beetles.  Specimens used for the photographs were borrowed from the Essig Museum of Entomology and the images were altered using the online program Pixlr-o-matic.  I hope you enjoy and learn a little about the wonderful world of beetles.

Males with Morphologically Modified Mouthparts are Militant Mates

malemandibles1[Alternate blog post title:  Mmmmmm….sexual dimorphism]

Sexual dimorphism occurs across many different groups of beetles and manifests itself in many different ways from antennal length to overall body size to extreme pronotal horns.  A recent article describes a different expression of sexual dimorphism, which the authors refer to as EMM or enlarged male mandibles.  The EMM discussed in this particular article focused on the beetle family Chrysomelidae, particularly those within the subfamily Crytocephalinae.  In addition to discussing the EMM, the authors described three new species – two from New Caledonia and one from Borneo.  All three of the species have incredibly impressive and very different expressions of EMM.  Below is the newly described species Scaphodius drehu with male and female comparisons along with the male’s obvious cartoon doppleganger.


Mandibles of this male more closely resemble Dick Dastardly’s mustache than they do the female’s mandibles.

So what are these incredibly modified mandibles used for?  Why do some groups of beetles have them while others don’t?  It doesn’t appear that they are used as a clasping device to hold onto females during mating because the head is a poorly placed area for such a function in many chrysomelids – many species are rotund and so the head of the male is far away from the female during copulation.  Instead the authors hypothesize that the mandibles are used in agonistic behavior – prying off other males that are already mating with females.  Interestingly, the authors surveyed the presence and absence of EMM across the Chrysomelidae and found that they are generally restricted to certain groups, indicating that this character may be phylogenetically informative.  Most of the species that have EMM have barrel-shaped bodies with high centers of gravity that are unstable, further supporting the hypothesis that the mandibles are used to dislodge opponents.

So, basically if you are an adorable rotund chrysomelid beetle, you’re more likely to have EMM than other chrysomelids that are not as adorably round.  Answering this question within a phylogenetic context would be interesting – are sexually dimorphic male mandibles correlated with body shape when accounting for shared ancestral history?  This can really only be addressed with a well-resolved phylogeny and to do that we need more research on Chrysomelidae taxonomy and systematics.

Check out this open access article – the pictures of the male mandibles for the newly described species are truly remarkable.

Reid CAM, Beatson M (2013) Chrysomelid males with enlarged mandibles: three new species and a review of occurrence in the family (Coleoptera: Chrysomelidae). Zootaxa, 3619 (1): 079–100.

Search for Subterranean Beetles

portola redwoods

Beetles are everywhere around you.  Don’t worry though, considering the vast number of species, beetles are a surprisingly innocuous bunch, at least towards humans.  They live basically everywhere and if you want to collect a variety of species, you need to employ a variety of collecting techniques.  My personal beetle collecting method of choice is using a beating sheet – taking a large sheet and placing it beneath a tree, lightly hitting that tree with a stick, and waiting for insects to fall onto the sheet.  But there are myriad methods to employ.  A few weeks ago, I traveled out to Portola Redwoods State Park* with my PI and a handful of additional arthropod lovers to set up some traps for some itsy, bitsy blind subterranean beetles.  As I mentioned, beetles are everywhere, including living between rock spaces underneath the ground.  So we lugged shovels, picks, and axes into the woods and buried traps up to a meter down beneath the surface.  We baited the traps with stinky things like rotten cheese and rotten meat…hopefully irresistable for the beetles. The traps are currently sitting out there, collecting beetles and waiting for our return – fingers crossed!  The traps will be checked in May to see if they actually did attract any creatures – beetles or otherwise.

If you would like to learn more about the details of this collecting method, I suggest you read the blog post here. (you’ll see that I also make a cameo in the post!)

Here are some photographs taken throughout the day:

*You should definitely not go out and attempt this method in your nearest state park – this is sure to ruffle some feathers.  We had express permission and the proper paperwork needed to conduct this work.  If you are thinking of trying this method, please make sure you have gone through all the proper channels to ensure that beetle collectors one and all keep their shiny [elytral] reputations. Thanks!