The Kaspari Lab

Thermal Diversity: the importance of a community perspective

In a Figure that Jon Shik says used a “shocking” color choice–but that the lead author (who is color blind) finds pleasant and peaceful–we plot the distribution of thermal maxima (or, CTmax, or “death temp”) of an assemblage of 87 ants from a Panama forest. Towards the left are  two measures of environmental temperature–“air temperature”, and the temperature the ants actually experience, that is,  the surfaces ants crawl upon. Note the differences in the distribution of thermal maxima for understory species versus those in the hot canopy. Finally, compare those distributions from a single tropical forest to those from Diamond’s excellent meta-analysis for ants from all around the world, and the best collection from those model organisms: lizards and fruit flies. 

Our takehome?  Tiny organisms experience superheated environments (think the steering wheel of your car on a hot day); ecological communities that experience change have a lot of thermal niches to shuffle; and the more we study the niches in a given community, and the environmental gradients they are adapted to, the more we need to deeply grok the biogeography of communities, not just populations, if we want to predict the ecological future of our planet. Oh, one more thing. Procyptocerus and Pseudomyrmex are high temperature champions; Cyphomyrmex and Strumigenys…not so much.

4 ants from BCI


Kaspari, M, NA Clay, J Lucas, SP Yanoviak, A Kay. (2015) Thermal adaptation generates a diversity of thermal limits in a rainforest ant community. Global Change Biology.

New Paper in Insectes Sociaux on Ants in Flight

Ant life cycles are complicated and varied, but in almost all species the queens have wings and fly through the atmosphere to mate and find new places to live. Drawing by Brittany Benson.  Text by Jackson Helms.

Go the publications page to download  Helms, JA, M Kaspari. (2015) Reproduction-dispersal tradeoffs in ant queens. Insectes Sociaux. 

When most people think of ants they probably picture a colony of wingless workers. Seen this way, it is easy to forget that ants are really just an odd family of wasps. Most ant queens, on the other hand, are indeed wasp-like and have wings and fly.

After developing from an egg virgin queens leave their birth nests and fly out into the world to mate, find a place to live, and start their own colonies. These aerial explorers—the mothers of the ant world—fascinate me. While most ant enthusiasts spend their time looking down at what worker ants do on the Earth’s surface, I spend my time looking up at what their elusive queens do in the atmosphere.

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Introducing “Marty’s World”

Marty’s World is Brittany Bensons’s view from the world below.

© 2015

The joy of click

Wienieish or not, I was actually chasing a special sort of buzz, a special moment that comes sometimes. One teacher called these moments “mathematical experiences.” What I didn’t know then was that a mathematical experience was aesthetic in nature, an epiphany in Joyce’s original sense. These moments appeared in proof-completions, or maybe algorithms. Or like a gorgeously simple solution to a problem you suddenly see after filling half a notebook with gnarly attempted solutions. It was really an experience of what I think Yeats called “the click of a well-made box.” Something like that. The word I always think of it as is “click.”

Might happen once a year, but there is nothing like it.

From Conversations with David Foster Wallace (Literary Conversations Series) by Stephen J. Burn

Litter Critters: Intro to the Mites and the ancestral group, the Opilioacarida

The greatest diversity of soil invertebrates is going to be found in the Acari, or, the mites.  At the mention of the word ‘mite’, plenty of folks will instantly think of ticks – those specialized, blood-thirsty mites in the suborder Ixodida.  Or, perhaps they may think of chiggers, also mites, which are the larvae of some tiny predators in the suborder Prostigmata.  Maybe, just maybe, they may think of clover mites.  Clover mites are also in the suborder Prostigmata, but are plant-sucking pests of people-loved plants.  Few will think on the beneficial mites, such as the helpful little oribatid mites that help recycle nutrients back into the soil, or the fearsome mesostigmatids that prey on plenty of plant-damaging pests. These predators are so helpful for this, in fact, that biocontrol companies will breed and sell them to gardeners as pest control.  

But first things first. What, technically, is a mite?

Mites are a subclass within the Arachnida.  It’s easy enough to count eight legs to put them in with this bunch, but what really makes them their own thing?  

It is supposed that the most ancient of mites had many abdominal segments, and over time these segments have fused.  As a result of this segmental amalgamation (aka tagmosis) the Acari now have two main body parts – the gnathosoma (the ‘mouth’), which is derived from the first two primitive segments and comprises mostly of the mouth parts, and the idiosoma, which is the ‘body’ essentially:  guts, legs, the works.  Mites have eight legs, two pedipalps and two chelicerae, with an incredible range of cheliceral morphs across the different acarine orders adapted to an equally diverse range of lifestyles.

Let’s start with the Opilioacarida, the most primitive group of mites. 

Opilioacarids are considered to be primitive because they have retained many ancestral characteristics that have long since been lost in the other mites.  They have an opisthosoma (abdomen) with 13 segments with remnants of primary segmentation marked on their backs, some have three pairs of ocelli (at most, other mites might have two pairs), all tarsi are divided (that’s the last tip of the legs) – a characteristic shared with other, non-mite arachnids, but not other mites.  The super fancy palpal apotele (a modified structure found at the tips of the palps in other parisitiform mites that looks like a little comb) is simply a pair of claws in the opilioacarids.  The opilioacarids are large (1.5-2.3mm long), can autotomize  (that is, cast off)legs when threatened, and regenerate them on the next molt. 

Given their diversity, any generalization about the diets of mites immediately suggests an exception. Plus the natural history of this group is ripe for exploration. That said, opilioacarids have been shown to feed on pollen, fungus, and arthropod remains, which they eat by taking in particulates.  They can look quite similar to the mite-like opilionids (Cyphophthalmi), which isn’t surprising, given their name.  Though they are found in many habitats such as caves, litter, under rocks in semiarid environments and forest litter in tropical and warm temperate regions of the world, there is still only a single family (Opilioacaridae) with eleven genera and thirty-eight species, over half of which have been described from the New World, mostly from North and Central America.  However, if you do come across one, they are spectacular!  Who could resist a creature with brilliant bands of blue or purple on it’s legs and back?

Illustration and Text by Brittany Benson

© 2015

Oh, snap!, molecular biology

I know, I know. Molecular biologists are an easy target for us field types. Just the other day Dr. Corrie Moreau, ant systematist extraordinaire, repeated an old joke with gusto over a Friday Skype:

So a stranger comes up to a sheepherder and says, “If I tell you how many sheep are in your flock, can I keep one?” After a moment, the sheepherder nods his assent. “You have 634 sheep.” the stranger says. Awestruck, the sheepherder says, “You win, take your pick.”. As the stranger walks away with his prize under his arm, the sheepherder yells out “Hey, you wouldn’t happen to be a molecular biologist would you?”. Now it was the stranger’s turn to be surprised. “How did you know?” he asked.  “You’ve got my dog.” the sheepherder replies.

So, anyway.

I’m perusing a recent issue of Science when I came across an article on how DARPA, a research arm of the defense department, is trying to automate the process of coming up with promising hypotheses. To which I say, “Hey, anything that helps, more power to ya.” But it was the target of their first efforts that floored me.  I’ll let Dr. Larry Hunter explain.

Building a system that actually produces scientific insight will not be easy, says computational biologist Larry Hunter of Smart Information Flow Technologies in Minneapolis, Minnesota, a co–principal investigator of one of the teams. The artificial intelligence community doesn’t have a strong track record at building systems that can develop useful causal hypotheses, he says. But molecular biology is a good place to try, he says, because it’s an area in which common sense plays a minor role; most of the knowledge is technical and available in textbooks and papers.

Now, I know, I know. Different challenges for different disciplines. Some of my best friends are molecular biologists. Just don’t let them near your dog.

From Science Magazine  30 January 2015347 (6221): 465

An achilles heel for bionic plants?

Cool news on the renewable energy front from  Joseph Torella and colleagues published in a recent PNAS.

The upshot: use photovolatic cells to provide electicity to a cobalt-phosphate catalyst that splits water into O’s and H’s, then feed those split-off H’s to an engineered soil bacteria, Ralstonia eutropha, to generate isopropanol (C2H80). Its a closed system–a bionic leaf about as efficient in generating CHOs as corn (without all those Nitrogen inputs).

Now as an ecologist, my thought is that these engineers better spend a lot of time generating new variants of Ralstonia. All that genomically identical biomass in all those bionic leaves across the land is going to be a rewarding target for the first virus that evolves a hankering for pampered Ralstonia.  I wonder if the cellulosic bioenergy folks are running into similar problems?

“We think we can do better than plants”: New “bionic leaf” makes fuel from sunlight –