An frog mounting a boot in a sex attempt gone wrong, known as “misdirected amplexus”, was what led researchers to ask “How could a behavior like this – one that does not generate offspring and thus should not be favored by natural selection – be so widespread?” Yes, in today’s episode of Studies We Like To See, it seems amphibians across the globe are trying to have sex with just about anything (including pythons).
The perpetrators star in a new paper: Finding love in a hopeless place: A global database of misdirected amplexus in anurans, published in the journal Ecology. In it, the authors explore exactly how widespread misdirected amplexus is, and what – if anything – compels these animals to do it.
Anurans are tailless amphibians from the order Anura, which includes frogs and toads. Through their research, the authors of the new paper pieced together 378 recorded examples of misdirected amplexus events, representing 156 species across 69 (nice) genera.
The sexually confused frogs and toads hailed from 52 countries, including every continent except for Antarctica – an outlier explained by the total lack of mammals, reptiles, or amphibians in the region.
All the amphibians included in the dataset had got it on with something they ought not to between 1920 and 2020, and the authors could pin each one down to the hour, month, and year in which the misdirected amplexus events took place. It’s hoped this data could one day help to explore how environmental conditions may drive the behavior.
In total, frogs and toads were found amplexing across amphibious species 282 times, with dead things 46 times, and with objects or non-amphibious species 50 times. The USA and Brazil proved to be hotbeds for misdirected amplexus events, being home to the highest number of records.
As sex-toy-touting humans, we can hardly claim to clutch our pearls over the topic, and object use in sexual contexts has been recorded among other apes – but what might lead a frog or a toad to try and mate with, say, a researcher’s boot?
“Frogs rely mainly on acoustic and visual cues (often combined) to find mates,” said corresponding author Filipe C. Serrano to IFLScience. “However, it depends on the species/group since some species are more territorial (usually arboreal species) and thus use calls to attract females, whereas others (e.g., most toads) use more of a ‘search and find’ strategy to look for females around breeding habitats. They may also use chemical or tactile cues, but these seem to be less important or at least mainly used after acoustic and visual ones.”
Of those mate-seeking approaches, misdirected amplexus was most commonly seen among the “search and find” species that breed explosively, indicating there’s an evolutionary aspect to sexing a boot. These animals are more likely to face big competition with lots of males to comparatively few females.
“[They use] a ‘clasp first, ask questions later’ strategy to ensure they find a mate,” explained Serrano. “This leads to individuals amplexing the first thing they see that may remotely resemble a female because the cost of not doing so, and potentially missing a female due to ‘choosiness’, is likely missing the opportunity to breed and generate offspring.”
Arguably, there’s choosiness and then there’s mating with a shoe, but it’s possible climate could influence the behavior. In more stable environmental conditions, more species could have year-round opportunities to mate rather than being restricted to an explosive breeding window.
The paper represents the first step in understanding trends surrounding misdirected amplexus in anuran species, and the authors are already starting on the next in investigating whether humans’ influence (such as habitat degradation, the introduction of invasive species, or even climate change) is increasing the number of events.
“The more answers we get from our data, the more questions arise,” Serrano said. “For example, do species amplex more similar (phylogenetically related) species? Is size preference a factor in misdirected amplexus? What could be the consequences of this behavior for amphibian populations?”
“We would like to gather more data, especially from under-reported regions such as Africa and Asia, and we encourage the use of citizen science to do so.”
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