Just a few daylight ago wereportedon how spiders are masters of not getting tangled in their own webs – but that does n’t mean the sleek traps are secure spaces for them . In the first known case of its kind , scientists have witnessed a spider being attacked and kill on its own web by a seemingly improbable marauder : a worm .
The wanderer , a combing - footed wanderer ( Helvibis longicauda ) , was minding its own business and chilling on its entanglement while guard its egg sac , when the tardily - moving , ill sighted flatworm pounced . The scene was stumbled upon by João Cardoso , one of the author on a late study describing the unusual depredation effect , back in 2014 in Brazil’sAtlantic Forest .
After taking the two resister back to the research laboratory for further study , Cardoso and co - source realise the dirt ball was a “ land planaria ” – a house of demesne - dwelling flatworms that prey on other invertebrates – belonging to the genusChoeradoplana . The spider , meanwhile , was found constricted and cover in sticky mucus , still clutching its egg Sauk .
A dirt ball might not fathom like the most fearsome of predators , but land planarians such asChoeradoplanaare much more threatening than they seem . While some have a taste for soft - bodied animals , such as earthworms , others are less picky and can raven on many organisms , include arthropod – the group to whichspidersbelong .
To good their prey of choice , predatory flatworms rely on physical force-out and corrosive mucous secretion , first enwrap around their quarry to immobilize them , before drench them in digestive fluid and snacking on the remains .
While the villainous turn fromChoeradoplanamay not be all that surprising , it ’s still incredibly rare to see flatworms interact with their fair game , and as such the authors believe this is the first case of predation of aweb - buildingspider by a land planarian ever to be line .
“ Our reflection broadens the oscilloscope of possible innate enemy of internet - building wanderer and the prey token of land planarians , ” the authors write in the work . “ It also indicate that these organisms can capture and overwhelm dangerous predatory arthropods , suggesting that even complex three - dimensional sticky webs can be unable against the attack of demesne planarians . ”
This , they go on to propose , is potential because the diabolical flatworm ’ mucus counters the web ’s adhesive attribute , allowing them to traverse the chain and access their quarry .
We may be more accustomed to ( though no less surprised by ) spiders overpoweringunlikely targets , but not so much the other way around .
“ A louse , predominate a spider ! It ’s really amazing , ” Cardoso toldNew Scientist .
The work is published inNeotropical Biology and Conservation .
