News Release 

Male spiders show their sensitive side

BMC (BioMed Central)

The sensory capacity of male spiders during mating may be higher than previously thought, a study in the open access journal Frontiers in Zoology suggests.

In most species, nervous tissue is considered to be an inherent property of male copulatory organs. In spiders, these organs are situated on appendages in front of the four walking legs. They were previously thought not to possess any nerves, muscles or sense organs, because they were thought to develop from the same cells that also make up a spider's claws, which are devoid of nervous and muscular tissue.

Peter Michalik, one of the corresponding authors of the study said: "Male spiders do not have direct sperm transfer organs, but transfer sperm via the tip of their pedipalps, which are transformed leg-like structures at the front of their bodies. They were thought to be numb and only recently two studies on two distantly related spider species suggested otherwise. Here, we show that the copulatory organs of male spiders have nerves and even contain sensory organs."

The research team, led by General and Systematic Zoology group of the University of Greifswald, Germany used a series of imaging techniques, including micro-CT. The authors tested the hypothesis that innervation of the spider copulatory organs may be part of the ground pattern of spiders, which means that it can be observed in all spiders. The authors showed that the copulatory organ in all species investigated in this study contained nervous tissue, which was located close to the glandular tissue of the spermophor, where sperm are stored before transfer into a female's body.

Sensory feedback provided by nervous tissue from the copulatory organ could be advantageous to male spiders in different ways, including adjusting their investment in the mating process, depending on whether a female mated previously or not, or to allow them to manipulate rival sperm already stored in the female's reproductive organs.

Peter Michalik said: "Our findings shed new light on the possible interactions between male and female spiders during mating. Males generally move their pedipalps during mating which might allow the male to transfer sperm and to assess the females during mating. The movement may even help in removing a predecessor's sperm from the female's sperm storage site, as happens in some species. In light of our findings, our current understanding of mating strategies in spiders needs to be revisited."

The findings pave the way for unravelling the sensory interaction of spider genitalia during mating and may help solve a mystery of spider reproductive biology; the uptake and release of sperm from the spermophor.

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Notes to editor:

1. Research article: The innervation of the male copulatory organ of spiders (Araneae) - a comparative analysis Dederichs et al. Frontiers in Zoology 2019 DOI: 10.1186/s12983-019-0337-6

After the embargo lifts, the article will be available here: https://frontiersinzoology.biomedcentral.com/articles/10.1186/s12983-019-0337-6

Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BMC's open access policy.

2. Frontiers in Zoology is an open access, peer-reviewed online journal publishing high quality research articles and reviews on all aspects of animal life. Frontiers in Zoology is the first open access journal focusing on zoology as a whole. It aims to represent and re-unite the various disciplines that look at animal life from different perspectives and at providing the basis for a comprehensive understanding of zoological phenomena on all levels of analysis. Frontiers in Zoology provides a unique opportunity to publish high quality research and reviews on zoological issues that will be internationally accessible to any reader at no cost.

3. A pioneer of open access publishing, BMC has an evolving portfolio of high quality peer-reviewed journals including broad interest titles such as BMC Biology and BMC Medicine, specialist journals such as Malaria Journal and Microbiome, and the BMC series. At BMC, research is always in progress. We are committed to continual innovation to better support the needs of our communities, ensuring the integrity of the research we publish, and championing the benefits of open research. BMC is part of Springer Nature, giving us greater opportunities to help authors connect and advance discoveries across the world.

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