Entrapment Bias of Arthropods in Miocene Amber Revealed by Trapping Experiments in a Tropical Forest in Chiapas, Mexico

Abstract

All entomological traps have a capturing bias, and amber, viewed as a trap, is no exception. Thus the fauna trapped in amber does not represent the total existing fauna of the former amber forest, rather the fauna living in and around the resin producing tree. In this paper we compare arthropods from a forest very similar to the reconstruction of the Miocene Mexican amber forest, and determine the bias of different trapping methods, including amber. We also show, using cluster analyses, measurements of the trapped arthropods, and guild distribution, that the amber trap is a complex entomological trap not comparable with a single artificial trap. At the order level, the most similar trap to amber is the sticky trap. However, in the case of Diptera, at the family level, the Malaise trap is also very similar to amber. Amber captured a higher diversity of arthropods than each of the artificial traps, based on our study of Mexican amber from the Middle Miocene, a time of climate optimum, where temperature and humidity were probably higher than in modern Central America. We conclude that the size bias is qualitatively independent of the kind of trap for non–extreme values. We suggest that frequent specimens in amber were not necessarily the most frequent arthropods in the former amber forest. Selected taxa with higher numbers of specimens appear in amber because of their ecology and behavior, usually closely related with a tree–inhabiting life. Finally, changes of diversity from the Middle Miocene to Recent time in Central and South America can be analyzed by comparing the rich amber faunas from Mexico and the Dominican Republic with the fauna trapped using sticky and Malaise traps in Central America.

Evolutionary and paleobiological implications of Coleoptera (Insecta) from Tethyan-influenced Cretaceous ambers

“…Authors such as Henwood (1993b), Penney (2002) and Solórzano-Kraemer et al (2015) experimentally analyzed different entrapment biases for arthropods in amber and arrived at different conclusions. Nevertheless, all the experimental work was performed by comparison with Cenozoic ambers and mainly produced by the genus Hymenaea (Angiospermae: Leguminoseae) which clearly differs from Cretaceous forest characteristics, as they were gymnosperm dominated.…”

Three new species of entimine weevils in Early Miocene amber from the Dominican Republic (Coleoptera: Curculionidae)

“…For select references on the insect and weevil diversity reported from Dominican amber see Arillo and Ortuño (2005), Poinar (2010), Yunakov and Kirejtshuk (2011), Poinar et al (2013), Poinar and Legalov (2015). Solórzano Kraemer et al (2015) discuss the effect of "entrapment bias" on the taxonomic composition of amber-preserved arthropod samples.…”

Pseudoscorpions (Arachnida, Chelonethi) in Mexican amber, with a list of extant species associated with mangrove and Hymenaea trees in Chiapas

“…Various types of traps were used, as described by Solórzano Kraemer and Stebner (2013) and Solórzano Kraemer et al (2015). The material was preserved in 70 % alcohol.…”

“…As part of a project to compare the fauna of Simojovel amber with that of modern mangrove habitats in Chiapas, extant arthropods have been sampled at Coquitos and La Cadena (Solórzano Kraemer and Stebner, 2013;Solórzano Kraemer et al, 2015). The extant pseudoscorpions obtained during that study are listed below.…”

“…As part of an investigation into the affinities between the Simojovel amber fauna and that of modern mangroves, Solórzano Kraemer and Stebner (2013) and Solórzano Kraemer et al (2015) sampled extant taxa from mangroves at Coquitos and La Cadena (Chiapas). The pseudoscorpions obtained during that study are also identified here.…”