The further adventures of Bipalium adventitium
I occasionally get comments to old entries, and recently I've gotten two to my 365 urban species post about the wandering broadhead planarian, affectionately known as the "landchovy" by my readers. This terrestrial flatworm is an predator of earthworms, an alien native to Indonesia or thereabouts, accidentally introduced into North America in exotic plants(probably). It was first detected in the middle of the continent (I want to say the Chicago area, but I forget exactly) and has spread, or been introduced to, both coasts and just about everywhere in between. I found several in Boston, which may be about the northernmost extent of their range on the east coast.
Photo by cottonmanifesto.
The two comments I received (you could have looked at them yourself by now) were from people who found these things and wanted to know more about them (a very good use of my blog, I think). One was found in Michigan, the other in Austin.
While researching this animal I discovered that they are the subject of study of one Pete Ducey, of SUNY Cortland. We corresponded a bit, and I learned quite a bit about these worms (which I have since passed on to you) and agreed to send him some if I found more, but soon it was winter and I didn't find any more. If I do find more, I'll send him some. If you find some, you should send them to him as well.
After I got the second comment about the landchovy, I decided to google its various names to see what information is floating out there (and, I admit, to find out how high my blog ranks as a source for what there is to know about predatory planaria). I found that Professor Ducey and his colleagues have published some interesting stuff about our favorite flatworm, the abstracts of which follow:
Ducey, Peter K., Gina Shaw, Jamie Tull, and Cara Fiore. (SUNY Cortland, Department of Biological Sciences, Cortland, NY 13045)
REPRODUCTIVE ECOLOGY OF THE INVASIVE PLANARIAN, BIPALIUM ADVENTITIUM, A PREDATOR OF EARTHWORMS
The invasive terrestrial planarian, Bipalium adventitium, is now widely distributed across temperate North America. These broadhead planarians, as predators of earthworms, could potentially have significant ecological impacts on forest, field, and anthropogenic habitats. The success of its continued invasion and the degree of its ecological impact will depend in part on the reproductive ecology and evolution of the species in this country. Through field and laboratory observations and experiments, we examined the reproductive parameters and their variability for four populations of B. adventitium from across its geographic range. Individuals are hermaphroditic, do not appear to self-fertilize, and are able to store sperm for months following mating. Like other terrestrial planarians, B. adventitium produces multiple, large egg capsules (13-30% of parental mass) containing small numbers of offspring (1-6 / capsule). Although there is considerable intraspecific variation in reproductive traits, most of this variation is within populations rather than between them, and does not appear to represent recent adaptation to local environments.
Kalina, Christine, Peter K. Ducey, Jamie Cerqua, Cara Fiore, Jamie Tull, and Monica Warner. (SUNY Cortland, Department of Biological Sciences, Cortland, NY 13045)
PREDATORY BEHAVIOR OF THE INVASIVE PLANARIAN, BIPALIUM ADVENTITIUM, A PREDATOR OF EARTHWORMS
The wandering broadhead planarian, Bipalium adventitium, is now widespread and locally abundant in North America. The ecological impact of these exotic planarians will be determined in part by their predatory behavior and interactions with potential prey (earthworms). The many species earthworms currently found in the Northeast differ in microhabitat use and in morphological and behavioral defenses. Using laboratory chambers, we investigated whether the flatworms could track and subdue a variety of earthworm species above and below ground and whether some earthworms had effective defenses against the planarians. We found that B. adventitium detected and followed chemicaltrails of earthworms and possessed the behavioral repertoire needed to subdue the prey in a range of microhabitats. They attacked and ate earthworms from all species tested, although the ability to escape varied among earthworm species. Defensive secretions gave Eisenia fetida some protection from Bipalium, and the antipredator behaviors of Amynthas sp. gave this earthworm species the highest rates of escape among those tested.
Interestingly (and perhaps predictably) Amynthas earthworms hail from Asia, and may have evolved their antipredator behaviors in response to the landchovy or a close relative. These behaviors include rapid writhing (they will apparently jump right out of your hand) and caudal autonomy (tail shedding).
Rest assured, I will try to keep abreast of all the latest developments in the study of the wandering broadhead planarian, so that you will be the most informed blog readers ever, when it comes to predatory terrestrial flatworms.
Photo by cottonmanifesto.
The two comments I received (you could have looked at them yourself by now) were from people who found these things and wanted to know more about them (a very good use of my blog, I think). One was found in Michigan, the other in Austin.
While researching this animal I discovered that they are the subject of study of one Pete Ducey, of SUNY Cortland. We corresponded a bit, and I learned quite a bit about these worms (which I have since passed on to you) and agreed to send him some if I found more, but soon it was winter and I didn't find any more. If I do find more, I'll send him some. If you find some, you should send them to him as well.
After I got the second comment about the landchovy, I decided to google its various names to see what information is floating out there (and, I admit, to find out how high my blog ranks as a source for what there is to know about predatory planaria). I found that Professor Ducey and his colleagues have published some interesting stuff about our favorite flatworm, the abstracts of which follow:
Ducey, Peter K., Gina Shaw, Jamie Tull, and Cara Fiore. (SUNY Cortland, Department of Biological Sciences, Cortland, NY 13045)
REPRODUCTIVE ECOLOGY OF THE INVASIVE PLANARIAN, BIPALIUM ADVENTITIUM, A PREDATOR OF EARTHWORMS
The invasive terrestrial planarian, Bipalium adventitium, is now widely distributed across temperate North America. These broadhead planarians, as predators of earthworms, could potentially have significant ecological impacts on forest, field, and anthropogenic habitats. The success of its continued invasion and the degree of its ecological impact will depend in part on the reproductive ecology and evolution of the species in this country. Through field and laboratory observations and experiments, we examined the reproductive parameters and their variability for four populations of B. adventitium from across its geographic range. Individuals are hermaphroditic, do not appear to self-fertilize, and are able to store sperm for months following mating. Like other terrestrial planarians, B. adventitium produces multiple, large egg capsules (13-30% of parental mass) containing small numbers of offspring (1-6 / capsule). Although there is considerable intraspecific variation in reproductive traits, most of this variation is within populations rather than between them, and does not appear to represent recent adaptation to local environments.
Kalina, Christine, Peter K. Ducey, Jamie Cerqua, Cara Fiore, Jamie Tull, and Monica Warner. (SUNY Cortland, Department of Biological Sciences, Cortland, NY 13045)
PREDATORY BEHAVIOR OF THE INVASIVE PLANARIAN, BIPALIUM ADVENTITIUM, A PREDATOR OF EARTHWORMS
The wandering broadhead planarian, Bipalium adventitium, is now widespread and locally abundant in North America. The ecological impact of these exotic planarians will be determined in part by their predatory behavior and interactions with potential prey (earthworms). The many species earthworms currently found in the Northeast differ in microhabitat use and in morphological and behavioral defenses. Using laboratory chambers, we investigated whether the flatworms could track and subdue a variety of earthworm species above and below ground and whether some earthworms had effective defenses against the planarians. We found that B. adventitium detected and followed chemicaltrails of earthworms and possessed the behavioral repertoire needed to subdue the prey in a range of microhabitats. They attacked and ate earthworms from all species tested, although the ability to escape varied among earthworm species. Defensive secretions gave Eisenia fetida some protection from Bipalium, and the antipredator behaviors of Amynthas sp. gave this earthworm species the highest rates of escape among those tested.
Interestingly (and perhaps predictably) Amynthas earthworms hail from Asia, and may have evolved their antipredator behaviors in response to the landchovy or a close relative. These behaviors include rapid writhing (they will apparently jump right out of your hand) and caudal autonomy (tail shedding).
Rest assured, I will try to keep abreast of all the latest developments in the study of the wandering broadhead planarian, so that you will be the most informed blog readers ever, when it comes to predatory terrestrial flatworms.