UNM Researchers Find When Mates Are Hard to Find, Males Are First to Go

Hair­worms are unique par­a­sites often encoun­tered by the pub­lic. Hair­worms infect crick­ets and grow within their host’s body cav­ity to lengths of 15–30 cen­time­ters. Infected crick­ets often invade homes and release worms into toi­lets, hot tubs, pet water bowls and fish tanks, unduly alarm­ing the pub­lic since hair­worms are not par­a­sites of humans.

When hair­worms com­plete their devel­op­ment, they manip­u­late the cricket’s behav­ior forc­ing them to com­mit sui­cide by jump­ing into water. Here the worms emerge from the host and begin the free-living part of their adult lives. Free-living male and female worms pair up, mate, and females lay eggs. Since hair­worms nat­u­rally occur singly in crick­ets, they must over­come the prob­lem of find­ing the oppo­site sex for mating.

Recently, a new species of hair­worm was dis­cov­ered from the Lake Vic­to­ria region of Kenya, Africa. The new species was named Paragordius oba­mai, in honor of Pres­i­dent Barack Obama, because it was dis­cov­ered near where the President’s father was raised and pater­nal step-grandmother resides.

The study, by Dr. Ben Hanelt of the Cen­ter for Evo­lu­tion­ary and The­o­ret­i­cal Immunol­ogy at the Uni­ver­sity of New Mex­ico, Dr. Matthew Bolek from Okla­homa State Uni­ver­sity and Dr. Andreas Schmidt-Rhaesa from Ham­burg Uni­ver­sity, Ger­many, is being spon­sored by the National Sci­ence Foun­da­tion (NSF), and was pub­lished recently in the jour­nal, PLoS ONE. It can be accessed at Going Solo: Dis­cov­ery of the First Partheno­genetic Gordiid.

The researchers inves­ti­gated this new species and found that it had come up with an inge­nious solu­tion to the prob­lem of find­ing mates by get­ting rid of males.

“Our results show that this species con­sists only of females and that these females alone pro­duce viable eggs,” Hanelt said. “In other species males are killed by bac­te­ria, but we have shown that this is not the case for this hair­worm, but rather it is very likely an evo­lu­tion­ary solu­tion to the dif­fi­culty of find­ing a part­ner in nature.”

Results from this study and future research could advance the work of sci­en­tists who are inves­ti­gat­ing the rea­sons why some ani­mals repro­duce asexually.

The dis­cov­ery “is of con­sid­er­able inter­est to biol­o­gists because the new partheno­genetic species is very closely related to another species, found in the United States, which con­tains both male and female worms,” said Bolek. “Since we have both of these species in cul­ture, we can now test var­i­ous hypothe­ses about the advan­tages and dis­ad­van­tages of sex, espe­cially in par­a­sites, and this work may even­tu­ally allow us to probe the genetic deter­mi­nants of repro­duc­tive strate­gies in parasites.”

For more infor­ma­tion, see Hair­worm Bio­di­ver­sity Sur­vey or con­tact Hanelt at (505) 277‑3174 or email at bhanelt@unm.edu.