Rovno Amber Ant Assamblage: Bias toward Arboreal Strata or Sampling Effect?

Abstract

Rovno Amber Ant Assemblage: Bias Toward Arboreal Strata or Sampling Eff ect? Perkovsky, E. E. -In 2015 B. Guenard with co-authors indicated that the Rovno amber ant assemblage, as described by G. Dlussky and A. Rasnitsyn (2009), showed modest support for a bias towards arboreal origin comparing the Baltic and Bitterfeld assemblages, although it is not clear whether this refl ects a sampling error or a signal of real deviation. Since 2009, the Rovno ant collection has now grown more than twice in volume which makes possible to check if the above inference about the essentially arboreal character of the assemblage is real or due to a sampling error. Th e comparison provided suggests in favour of the latter reason for the bias revealed by B. Guenard and co-authors. Th e new and larger data on the Rovno assemblage show that the share of non-arboreal ants is now well comparable with those concerning the Baltic and Bitterfeld assemblages. Th is holds true for the both total assemblages and subassemblages of worker ants only. Th is paper is a second in the series of papers dedicated to memory of Prof. Gennady Dlussky, who established a new standard in palaeomyrmecologyModern ant assemblages were compared to the fossil assemblages of the Baltic, Bitterfeld, Rovno and Scandinavian amber deposits compiled by Dlussky and Rasnitsyn (2009) by Guenard et al. (2015).Late Eocene amber assemblages in the paper of Dlussky and Rasnitsyn (2009) were represented by over 16,700 inclusions determined to the species level (respectively Baltic = 14,915, Bitterfeld = 1,039; Rovno = 501; and Scandinavian = 271).To evaluate taphonomic biases in generic composition, Guenard et al. (2015) classifi ed the extant genera known from the fossil records into one of the following categories: arboreal, epigaeic, hypogaeic, arboreal + epigaeic, epigaeic + hypogaeic, arboreal + epigaeic + hypogaeic (no genera were classifi ed as arboreal + hypogaeic). Furthermore, they considered if the fossil specimens in each genus were known as worker (nonfl ying individual) or alate (fl ying gyne or male). Th is is an important distinction because many hypogaeic species are overrepresented by alate individuals trapped in resin during mating fl ights (Dlussky, Rasnitsyn, 2009).Th e multinomial logistic regression analysis (Guenard et al., 2015) supports an epigaeic origin of the species richness across subfamilies when all fossil deposits sites are considered. Th e result is, however, slightly diff erent when fossil assemblages are considered individually. While the Baltic amber and Bitterfeld ones relate more strongly to the epigaeic or epigaeic + hypogaeic origin, the Rovno amber assemblage appears biased towards the arboreal origin. Guenard et al. (2015) indicate that Rovno assemblage shows modest support for a bias towards arboreal origin, although it is unclear whether this refl ects a sampling error or a signal of real deviation.

Ant‐induced evolutionary patterns in aphids

“…110–90 Mya (Grimaldi & Agosti, 2000; Barden & Grimaldi, 2016) broadly concurrent with diversification of the aphids. A review of the known syninclusions of ants and aphids in Cenozoic amber (Kutscher & Koteja, 2000; Perkovsky, 2006, 2007, 2009a, 2009b; Perkovsky et al ., 2012) shows little co‐occurrence, despite many fossil ants (Dlussky, 2011; Perkovsky, 2016a, 2016b) and aphids (Heie, 1967; Wegierek & Mamontova, 1993) being known from that period. Nevertheless, some differences in co‐occurrence of ants and aphids in amber syninclusions between Baltic and Rovno ambers (Eocene, around 50–35 Mya), connected with climate differences, indicate that within that period a relationship between ants and aphids had already developed a mutualistic character (Perkovsky, 2012).…”