Dickless Spanish Microworm Has Strange Approach To Sex


Tom Hale

Senior Journalist

clockMar 2 2017, 17:04 UTC

A Myolaimus ibericus seen by scanning electron microscope. Joaquín Abolafia

It might not be big, nor look particularly pretty, but this microworm might just have the weirdest sex life of all creatures great and small. Believe it or not, they may also be of great use for climate scientists. 

Myolaimus ibericus, or the "microworm of Jaén", was recently found amongst the orchards of Puente de la Sierra in Jaén, south-central Spain. It caught the attention of biologists studying in the area because, unlike the vast majority of animals, this tiny nematode has no penis or any kind of copulatory organ.


It turns out, the researchers from the Spanish Foundation for Science and Technology had discovered a new species. Their study is published in the journal Zootaxa

Since the males have no reproductive organ, they have to resort to other methods to get their rocks off. They pump sperm into a sack found on the genitals of the female, when its skin moves.  "From here, the sperm, which is large and has pseudopods (extensions), enters the female's genital tract and fertilizes the ovules," lead author Joaquín Abolafia, a biologist at the University of Jaén, explained The eggs that develop are covered in small spines, which he calls very "unusual among nematodes." 

While us genital-obsessed humans might laugh at these creatures, they could actually prove useful in helping us understand climate change. Living in the dry and arid hills of the Iberian Peninsula, these 0.5 to 0.8-millimeter-long microworms feed on the bacteria they find in decomposing organic matter and can survive with very little water.


"These small animals serve as bioindicators of soil quality, as well as indicators of the presence of waste (especially fecal), of the existence of desertification processes and, ultimately, of climate change," Abolafia added.

The scientists concluded this tiny, weird creature is actually of global significance in nematology: "It is a strange species with unusual biology, belonging to a very rare group of nematodes, and it is found in Jaén. This makes it unique on the Iberian Peninsula."

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