Mating and aggregative behaviors among basal hexapods in the Early Cretaceous

Abstract

Among the many challenges in paleobiology is the inference and reconstruction of behaviors that rarely, if ever, leave a physical trace on the environment that is suitable for fossilization. Of particular significance are those behaviors tied to mating and courtship, individual interactions critical for species integrity and continuance, as well as those for dispersal, permitting the taxon to expand its distribution as well as access new habitats in the face of local or long-term environmental change. In this context, two recently discovered fossils from the Early Cretaceous amber of Spain (ca. 105 mya) give a detailed view of otherwise fleeting ethologies in Collembola. These occurrences are phylogenetically spaced across the class, and from species representing the two major clades of springtails—Symphypleona and Entomobryomorpha. Specifically, we report unique evidence from a symphypleonan male (Pseudosminthurides stoechus Sánchez-García & Engel, 2016) with modified antennae that may have functioned as a clasping organ for securing females during mating on water’s surface, and from an aggregation of entomobryomorphan individuals (Proisotoma communis Sánchez-García & Engel, 2016) purportedly representing a swarming episode on the forest floor. We demonstrate that the mating behavioral repertoire in P. stoechus, which is associated with considerable morphological adaptations, likely implied elaborate courtship and maneuvering for guarantee sperm transfer in an epineustic species. These discoveries reveal significant behaviors consistent with modern counterparts and a generalized stasis for some ancient hexapod ethologies associated with complex mating and courtship and social or pre-social aggregations, so critical to specific constancy and dispersal.

Chemical communication in springtails: a review of facts and perspectives

“…Evidence for the existence of sex (Waldorf 1974a) and aggregation pheromones (Mertens and Bourgoignie 1977;Verhoef et al 1977a, b) stimulated studies on olfactory signals involved in communication between congeners and mates in an environment and a zoological group such as soildwelling species where visual systems are rudimentary (Leinaas 1983;Pfander and Zettel 2004;Porco et al 2009). Remarkable fossils preserved in Early Cretaceous amber allow describing a courtship behaviour in a Symphypleona and an aggregative behaviour in an Entomobryomorpha, thus suggesting the presence of pheromones more than 105 Ma ago (Sánchez-García et al 2018). However, information on the importance of chemical communication for coexistence or avoidance and the evolution of collembolan species is still scarce Bengtsson 2004b, Wertheim et al 2005).…”

Diversity of Collembola on Various Post-Rehabilitation Land Covers

“…Collembola aggregations result from interactions with less favorable or even suitable environmental factors (Widrializa, et al, 2015). Aggregative behavior of Collembola is influenced by pheromones (Sánchez-García et al, 2018), and is carried out to mitigate drought and temperature stress or any undesirable conditions (Potapov et al, 2020).…”

Inferring collective behaviour from a fossilized fish shoal

“…If so, then surface heterogeneity cannot explain the dense aggregation of fish in the specimen. Considering that dead bodies in an assemblage of carcasses would be positioned all over the slab (this is true for other mass mortality fossils [10,31,32] and electronic supplementary material, figure S6), the observed localized aggregation is likely to be the result of behaviour rather than an artefact of fossilization (see [41] for a discussion of this issue). Also, the sediment is fine-grained mud, which is one criterion for an in situ rather royalsocietypublishing.org/journal/rspb Proc.…”