Back from the dead

Today I read an account of a fly, which was thought to be extinct, being found in Spain last year.  The fly, Thyreophora cynophila, was snapped by a nature photographer who posted an image of the fly on-line in the hopes of an identification.  No guesses came in for a long time as to the identity of the critter – which is odd for Europe with its profusion of professional and amateur entomologists.  But eventually someone identified the distinctive dipteran as a species not seen for over a century and a half.  Even back then it was so rare that only 16 curated specimens exist in the world.

The formerly-extinct bone-skipper fly (Thyreophora cynophila); female (top) and male (bottom).

The rediscovered fly, known as the “bone-skipper”, is a insect that is a specialist on the exposed bone marrow of dead mammals in the stages of late decay.  A prominent feature is its orange head which is glows at night.  A scientific paper out this month documents the success of trapping more of these flies, along with the authors’ theory as to why this species has disappeared for so long, citing three main reasons.  The first is that the predatory mammals, such as wolves and bears that can break open the large bones of mammalian prey, have all but disappeared in Europe. This is thought of as a limiting factor on the overall amount of exposed marrow in which the flies deposit their eggs.  A second reason is that sanitation practices in Europe have changed significantly in the last couple of centuries and any exposed bone marrow from livestock butchering is soon contained and disposed of for reasons of public health.  Perhaps the biggest reason that no one in recent history has seen this fly is that it appears to be active only in the coolest months of the year – when entomologists are rarely out collecting.  By far, most insects only forage and mate at times of the year when the ambient temperatures allow their “cold blooded” physiologies to be active. So aside from the severe shortage of very old, ungulate bone marrow, it turns out that people just weren’t looking at the right time.

While we may not notice the extinction of an insect as much as we do some larger species, such as birds and mammals, there have been a few notable insect species that have been lost to extinction.  Among them are the Antioch Katydid (Neduba extincta, which used to be found among the sand dunes of California), the Rocky Mountain Grasshopper (Melanoplus spretus, which used to blacken the skies of the western U.S. in great plagues), and the Xerces Blue butterfly (Glaucopsyche xerces, which also inhabited the sand dunes in California and was last seen fluttering around in the vicinity of Golden Gate Park).  All of these species are extinct as a result of habitat loss to development and modification, as well as pressure from invasive species.  The extinction of the afore-mentioned Xerces Blue became the inspiration for an biological conservation organization, the Xerces Society, which currently works to save endangered invertebrates and their critical habitat from succumbing to the same fate as its namesake.

The extinct Xerces blue butterfly (Glaucopsyche xerces) and namesake of the invertebrate conservation organization, Xerces Society.

Like the recently-rediscovered bone-skipper fly that has revealed itself as more alive than previously thought, there have been other exciting revelations in the last decade where living populations of insect species, that were previously declared extinct, have been found clinging to a less-defunct classification.  Plants and animals that perform this miracle of coming back from the dead are collectively referred to as “Lazarus species”.  One such insect that managed to come back to life is the Lord Howe Island stick insect (Dryococelus australis) which was declared extinct in 1930.  Much like the British Admiral for whom the Lord Howe Island Group was named, the stick insect bearing his name survived several brushes with extinction.  A population of 30 stick insects was discovered by entomologists in 2001 on a hellish, isolated, rock feature in the Lord Howe Island Group known as Ball’s Pyramid.  The overall population of the stick insects has since increased to about 450 individuals through a government conservation breeding program and some of those individuals have since been released on Lord Howe Island (following an island-wide rat eradication program).

The formerly-extinct Canterbury knobbed weevil (Karocolens tuberculatus), last seen in 1922 but rediscovered in 2004.

Several insects that have also managed to disappear for decades or centuries and, ostensibly, from the face of the Earth. For example, several of the moths in the diverse genus Omiodes are endemic to Hawai’i, a number of which have been declared extinct.  Some of the species that hang on are still being hammered by exotic predators and parasitoids that have been intentionally introduced to control crop pests, as well as from contact with agricultural insecticides.  However, some of the Omiodes species that were declared extinct have recently been rediscovered by researchers at the University of Hawai’i.  Tentative plans for conservation programs to help save these species are in the works.  The short-necked oil beetle (Meloe brevicollis) was also declared extinct long before being discovered again.  The larvae of this beetle are parasitic on solitary bees and feed on their eggs.  It was last seen in the 1940s and its numbers were likely curtailed as a result of farming activity, but a small population was rediscovered in 2007 on the island of Devon. Another beetle, the Canterbury knobbed weevil (Karocolens tuberculatus) was last seen in 1922 near Christchurch, New Zealand… that is until it was discovered by a graduate student studying its food plant in 2004. Four specimens of this nocturnal critter were collected at a light trap and submitted to the Canterbury Museum where it was determined to be the AWOL weevil.

New Zealand was also an important refuge for another insect that went extinct in its home range of the UK. Short-haired bumblebees (Bombus subterraneus) were last seen in Great Britain in 1988. The reason for this is likely due to the disappearance of wildflower fields that once dominated much of the countryside. With the loss of this vital nectar source and in conjunction with all of the other stresses brought on by development and a modern world (pesticides, pollution, parasites, etc.) carving out a living in the UK just got too difficult for this bee and it disappeared. However, the same insect was introduced to New Zealand over a century ago when it was still a British colony. Once released it proceeded to pollinate crops and continued to survive. The return to its homeland was complete this summer when several bees collected in New Zealand were released at restored wildflower fields in Kent, in southern England. Over the past several years a number of farms and other rural properties have gone through intense rehabilitation efforts to restore them to traditional wildflower fields by removing invasive weeds and instituting conservation measures to encourage growth and proliferation of native, nectar-producing plants. The silver lining to this story is that the effort to create a welcoming habitat for the short-haired bumblebees has resulted in the rebound of populations of five other rare, native bee species that also pollinate wildflowers and crops.

The gladiator Austrophasma rawsonvillensis (Notoptera: Mantophasmatidae), representative of a group that was once thought only to be found in the fossil record. photo by Mike Picker

Its rare to recover or rediscover a species that’s been declared extinct, but it’s even more unlikely to find an entire suborder of insects that’s disappeared.  However that’s exactly what happened in 2002.  It was an exciting time to be an entomologist when the Mantophasmatodea were found, alive and well, on the Brandberg Massif in Namibia (a virtual island in the sky).  These carnivorous insects superficially resemble grasshoppers and stick insects, but are most closely related to the obscure insect family Grylloblattaria. They are a stout little creatures that live in a landscape with the most diverse and abundant scorpion fauna in the world, for which they definitely earn the title of gladiators.

More recently, I’ve had the privilege of working in the lab of Dr. Rob Dunn during the reemergence of a couple ant species that are were declared extinct. Simopelta minima is a Brazilian species of ant that was named from four ant workers that were found in soil samples in on a cocoa plantation in the 1980s. The plantation has since been converted to farmland and the ant was considered extinct by the Brazilian government. However, more workers of the same species were discovered over 1,000 km away from the original collection site. The authors of the paper documenting this rediscovery suggest that the reason this species went undetected for so long is due to the paucity of sampling being carried out. People just weren’t looking hard enough.

An adult Pachycondyla chinensis attacking a termite, its main prey. photo by Benoit Guénard

One other person in Rob’s lab that is looking hard is Benoit Guénard, a PhD student in the lab. He’s a virtual Sherlock Holmes of ants and has made several interesting discoveries in his short time at NC State University. In 2006, during his effort to become more familiar with the ant fauna of North Carolina, Benoit found an ant that he was unable to identify. He found this same species in multiple areas of Piedmont and Coastal NC and in greater numbers than the other ant species. After trawling through numerous identification keys he determined that the ant was not native to NC, but rather it was native to Asia.  He also discovered that it was virtually unknown and unstudied in NC, despite its ubiquity and dominance here. The invasive ant, Pachycondyla chinensis is not new to the state.  It has been living – mostly undetected – among the forests, fields and streets of NC for nearly a century. Despite being a virtual unknown to North Carolinians, particularly compared to the other invasive ant that people here know (the fire ant, Solenopsis invicta), Benoit’s ant has a sting that poses a greater health concern to those that enjoy the outdoors. The sting of P. chinensis is painful and can cause severe swelling and anaphylaxis.  Largely through Benoit’s discovery, this species is now confirmed to be throughout much of the Eastern US and has been spotted in locations from Connecticut to Florida and as far east as Tennessee and Alabama. Yet three or four years ago, hardly anyone was even aware of it.

The rarest ant in North America, Amblyopone trigonignatha. photo by Benoit Guénard

Benoit was also the first person to find another ant that was discovered in 1948 and hasn’t been seen since.  The ants in the genus Amblyopone are primitive (for ants) and commonly referred to as “Dracula ants” in reference to the behavior exhibited by workers of feeding on the hemolymph of their colony’s larvae. After 61 years of no contact, Amblyopone trigonignatha was found in Benoit’s backyard (literally).  On one particularly sunny day in Raleigh during this past January, Benoit decided to take some photos of ants at his home and found what he thought was another, more common species of Amblyopone in the backyard.  He snapped a few good photos before… [gasp]… letting it go. There is a good, first-person account the story in the Myrmecos Blog, but the punchline is that another myrmecologist saw the photos months later and contacted Benoit with his thought that it might be the ant that is often considered the “rarest ant in North America.”

So naturalists are still out there, hunting elusive creatures that are waiting to be discovered and rediscovered. The likelihood that we’ll find another extinct suborder or family is low, but the resurrection of the bone-skippers, gladiators and Dracula ants from the annals of history is an exciting reminder of what may still be out there and waiting for us to find it… again.

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About Scot Waring

I'm a nature freak who loves getting out, down and dirty. My passion for nature has, somewhat unexpectedly, driven me to a professional career working with insects and people that love them.
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