Antkey Mobile released

The USDA APHIS ITP team is pleased to announce the latest addition to our mobile app collection: Antkey Mobile. Developed in cooperation with the tool’s author, Eli Sarnat, and Australia’s Identic team, this app is based on ITP’s web-based tool, Antkey.
Lucid Mobile apps offer you the identification keys you’ve come to rely on from the convenience of your smartphone or tablet. Antkey Mobile (free for Android or iOS) allows you to take your Lucid key with you into the field for surveys and screening, even if your field site lacks internet access.
This key allows both specialists and novices to easily identifyinvasive, introduced, and commonly intercepted ant species from across the globe. You can help confirm whether you have found the correct species by comparing your specimen with the images and descriptions on the fact sheets, which are included for each species.

Tramp ant caught globetrotting under false name


Tramp ant caught globetrotting under false name

December 14, 2015
Tramp ant caught globetrotting under false name
A specimen of Pheidole indica, an ant species from Asia that has been spreading across the globe under the name Pheidole teneriffana. Credit: Dr. Eli Sarnat

A century-old mystery surrounding the origin of an invasive ant species was recently solved by an international team of scientists. Since 1893, when it was first discovered as an invasive species in the Canary Islands, entomologists have been debating where this mystery species came from. While some insisted on the Mediterranean, some proposed Arabia and others argued for Africa. The correct answer? Asia.

The authors of the study, published in the open-access journal ZooKeys, solved the taxonomic puzzle by fitting together disparate pieces of evidence. “I was having a terrible time trying to distinguish this one Asian from the mysterious ant that was coming in on shipments from the Caribbean, Europe and Africa,” says Dr. Eli Sarnat, University of Illinois, about his research at the Smithsonian on tramp that were intercepted at US ports.

Tramp ants, many of which are pest species, are spread across the globe by stowing away in the cargo of ships and planes, thus posing rising environmental, food security and public health concerns.

The same day Sarnat was working on the mysterious ant in the Smithsonian, he received an email from Dr. Evan Economo, Okinawa Institute of Science and Technology (OIST). Economo and Dr. Georg Fischer, also affiliated with OIST, had included Madagascar samples of the species in a genetic analysis, and the results unexpectedly placed it within a group of Asian species. The closest genetic match to the enigmatic ant turned out to be the very same Asian species that Sarnat had found in the Smithsonian collection.

Tramp ant caught globetrotting under false name
A showing the global distribution of Pheidole indica, with the native regions in blue and the invaded regions in red. Credit: Dr. Eli Sarnat

The last piece of the riddle was discovered thanks to the painstaking work of Dr. Benoit Guénard. Guénard, a professor at the University of Hong Kong, had spent years mapping the global distributions of every ant species known to science. When he compared the ranges of the mysterious ant with the common Asian species, the two fit together like a jigsaw puzzle.

Evidence gathered from classic taxonomy, modern genetic analysis, and exhaustively researched distribution maps all pointed to the same conclusion.

“What had long been considered two different species—one found across a wide swath of Asia and the other a tramp species spread by humans across Europe, Africa, the Americas and Australia—are actually one single supertramp species,” Economo explained. “It is striking that we had these two continental super-common invaders with almost entirely complementary ranges right under our noses, yet until now no one noticed they were actually the same species,”

More information: Sarnat EM, Fischer G, Guénard B, Economo EP (2015) Introduced Pheidole of the world: taxonomy, biology and distribution. ZooKeys 543: 1-109.DOI: 10.3897/zookeys.543.6050

Read more at:

Morphometric measurements from vector images

I’ve been trying to find a good method for quantifying just how spiny any given ant species is. Among Pheidole ants, we see this interesting phenomenon where certain clades have developed elaborate spines and armature relative to the rather conservative morphology of their relatives. This ‘spinescent’ morphotype has evolved independently in at least four Pheidole lineages.

Morphometric measurements from vector images from Eli Sarnat on Vimeo.

So how to measure spinescence? Ideally we’d have 3D tomography of representative specimens from each species, but that’s not very feasible. Using a stage micrometer to measure spine length relative to something like head width is another option, but it is really difficult to account for the curves and bifurcations in some of the structures.

My solution is to create a spinescence index, defined as the ratio of spine perimeter to body perimeter. In other words, what percentage out the specimen’s 2D perimeter is devoted to spines? It’s not a perfect solution, but it’s the best I’ve come up with in terms of accuracy and feasibility.

A few useful tricks for using Endnote

I’m not sure how widespread this issue is, but I find the instant formatting function of Endnote x7 to become painfully slow after my MS Word manuscripts include 100 or so references. I’d hope that there is an elegant solution to this, but I haven’t found it yet. My current strategy for maintaining sanity while composing reference-rich manuscripts is to leave the field codes unformatted and disable instant formatting. After a bit of reverse engineering I now use the following field codes to achieve the desired reference formatting. I then periodically format the references to make sure everything looks as expected. Hope this helps anyone stuck in similar predicaments.

In these examples, the author = Forel, and the year = 1909.

{Forel, 1909 #10514} = (Forel, 1909)
{Forel, 1909 #10514@@author-year} = Forel (1909)
{Forel, 1909 #10514@@hidden} = only show in bibliography
{Forel, #10514} = show only author
{, 1999 #10514} = show only year

New ant species described from Fiji – Proceratium vinaka

Francisco Hita Garcia, known more familiarly as Paco, took the lead on describing a newly discovered species of Proceratium from Fiji [1]. Vinaka is the Fijian word for thank you. My friend Moala Tokota’a told me it is the most important word in the whole language.

Proceratium vinaka

Proceratium vinaka — a new species of ant described from Fiji

To call this blind, inconspicuous species rare is rather understated. In fact, there is only one single individual worker of this species ever collected in the whole wide world. I remember the moment I first laid eyes on it. A group of us including Rosie Gillespie, some of the crew from WCS and my wife Julia were working our way down from the misty peak of Mt. Devo (Vanua Levu) after a long day. There is a single track unsealed road we were following that winded down the mountain. The upper elevations of Mt. Devo are as pristine a forest as one will find in Fiji, but there was an old garden site on the way down that was transitioning back to jungle.

Distribution map of Fijian Proceratium species

Distribution map of Fijian Proceratium species

I was scanning the ground on hand and knee, searching for a last score before heading back to the truck, when this slow-moving stout and armored ant caught my eye. It looked out of place foraging on the surface. The line from Notorious B.I.G. shoot first ask questions last compelled me to get this special creature secured in a vial before it went to ground in the leaf litter. I stuck around for a few more minutes hoping to find more of its kin, but to no avail.

That was ten years ago. Since then this single specimen has been mounted on an insect pin together with various labels detailing the location, date and circumstances of its capture. It has been resting quietly in an insect cabinet, the sole known representative of its species, awaiting a name. Thanks to the effort of Paco and Evan, Proceratium vinaka is the 12th new ant species we’ve described from Fiji over the past decade. Only 34 more to go!

[1] Hita Garcia F, EM Sarnat, EP Economo (2015) Revision of the ant genus Proceratium Roger (Hymenoptera, Proceratiinae) in Fiji. ZooKeys 475: 97-112. doi:10.3897/zookeys.475.8761 [pdf]

Using photoshop to take morphometric measurements

Taking morphometric measurements using specimen photographs from Eli Sarnat on Vimeo.

In this tutorial I use Adobe Photoshop cs6 Extended Version and a specimen photograph of an ant head to take morphometric measurements. I set a custom measurement scale in Photoshop calibrated to the scale bar embedded in the photograph, then record the measurement taken by using the Ruler Tool. Remember, the measurement will only be as accurate as the scale bar embedded in the photograph. So if the scale bar was not calibrated correctly at the time the photograph was taken, any derivative measurements will also be inaccurate.

Scratchpads tutorial: dealing with nomenclatural changes (new combinations)

Scratchpads tutorial: dealing with nomenclatural changes (new combinations) from Eli Sarnat on Vimeo.

In this tutorial I show one way for updating terms in the biological classification to reflect nomenclatural changes. The situation I deal with here is for a species included in the site which has recently been transferred to a different genus. This nomenclatural act is known in taxonomic jargon as a ‘new combination’.

In this case, the species Monomorium destructor has been transferred to the genus Trichomyrmex. I change the Unit 1 name (genus) of the term Monomorium destructor to Trichomyrmex. Then I add a new taxon term ‘Monomorium destructor‘ as a child to Trichomyrmex destructor and classify it an invalid name associated with Monomorium destructor. This way all the content previously associated with Monomorium destructor will now be associated with Trichomyrmex destructor, and anytime someone searches for the now invalid name Monomorium destructor the user will be directed to the valid combination Trichomyrmex destructor.

Pheidole flavens-complex introduced to the southwestern Pacific

Here’s the story behind the new Bioinvasions Records article on that just came out. Christian Rabeling and Ed Wilson went to Vanuatu a few years back in 2011 because it was one of the few Melanesian islands that Wilson had never collected from. They collected all the ants they could find in a general survey and kindly sent their Pheidole to the Economo lab at OIST so that I could match them against our other Pacific Pheidole collections and Evan could include them in our phylogenetic analysis. Christian and Ev caught some great Pheidole from the island, including this beautifully spinescent endemic from the sexspinosa complex shown below (CASENT0282641).

An elegant Vanuatu endemic ant species (Pheidole epem198, CASENT0282641) from the Pheidole sexspinosa complex

But one species came out in an unexpected branch on the phylogeny. Instead of coming out with the Old World clade with all the other native Melanesian ants, this one species was reliably nested within the New World clade. It’s closest relatives on the tree were two species that had been included in Corrie Moreau’s 2008 Pheidole phylogeny and id’d as P. moerens and P. flavens–both of which are considered to be invasive.

Major worker of a species from the Pheidole flavens-complex from Espiritu Santo, Vanuatu; collection code CR111110-15, specimen code CASENT0248836. (1) Lateral view, (2) fullface view, (3) dorsal view, (4) hypostomal bridge.

Major worker of a species from the Pheidole flavens-complex from Espiritu Santo, Vanuatu; collection code CR111110-15, specimen code CASENT0248836. (1) Lateral view, (2) fullface view, (3) dorsal view, (4) hypostomal bridge.


Minor worker of a species from the Pheidole flavens-complex from Espiritu Santo, Vanuatu; collection code CR111110-15, specimen code CASENT0248835. (5) Lateral view, (6) fullface view, (7) dorsal view

We wanted to let other researchers know about the spread of this trampy species into the Pacific, so we wrote up a rapid communication article for Bioinvasions Records. The idea was to get the basic information about the new discovery out as quickly as possible, so others in the region could be on the lookout for additional incursions.

The most frustrating part of this study was trying to get a name on the species. Unfortunately, the taxonomy of P. flavens and its close relatives like P. moerens and P. exigua is a super sticky mess, rife with infra-specific names, lost holotypes, and inaccurate determinations. It seems like these taxonomic morasses plague trampy species (like P. flavens and friends) much more often than your average ant species.

Why is it that trampy species so often belong to species-complexes? What are species-complexes, anyways? I suppose I’d define them as geographically distinct populations that are somewhere on the continuum of streching from a recently coalesced species radiation on one end to a network of geographically isolated groups with some low amount of gene flow still persisting. For the taxonomist or even the molecular systematist there is no clear way to know whether to call these things five geographically isolated species or one widespread species.

Whatever the population on Vanuatu turns out to be, it doesn’t match the neotype of P. flavens or the syntypes of P. moerens, so for now we have to settle for calling it a member of the flavens-complex and hope that someone tries to untangle this taxonomic knot in the near future.

EM Sarnat, C Rabeling, EP Economo & EO Wilson (2014) First record of a species from the New World Pheidole flavens-complex (Hymenoptera: Formicidae) introduced to the southwestern Pacific. Bioinvasions Records 3: 301-307. | PDF


How to identify Solenopsis invicta using Antkey

In this tutorial I demonstrate a few different approaches to identifying Solenopsis invicta, also known as the Red Imported Fire Ant (RIFA), using Antkey. The key can be accessed at

How to identify Solenopsis invicta using Antkey from Eli Sarnat on Vimeo.

How to use Antkey’s Lucid3 interactive key

In this tutorial I demonstrate how to make the most effective use of Antkey’s interactive Lucid3 key for identifying invasive and introduced ants. There are tips on how to use features like the ‘best’ and ‘next best’ buttons, what the different panels mean, how to make effective use of thumbnail and pop-up images and how to adjust the text size.

How to use Lucid Key for identifying ants from Eli Sarnat on Vimeo.