Reproductive motivation in the context of the COVID-19 epidemic: Is there evidence for accelerated life history dynamics?

Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1614029114 ◽

2017 ◽

Vol 114 (5) ◽

pp. 1069-1074 ◽

Cited By ~ 17

Author(s):

Helder Gomes Rodrigues ◽

Anthony Herrel ◽

Guillaume Billet

Keyword(s):

Life History ◽

Body Mass ◽

Life Histories ◽

Life History Trait ◽

Phenotypic Traits ◽

Structural Constraints ◽

Dental Eruption ◽

Accelerated Life ◽

Environmental Variations ◽

Adaptive Nature

Investigating life history traits in mammals is crucial to understand their survival in changing environments. However, these parameters are hard to estimate in a macroevolutionary context. Here we show that the use of dental ontogenetic parameters can provide clues to better understand the adaptive nature of phenotypic traits in extinct species such as South American notoungulates. This recently extinct order of mammals evolved in a context of important geological, climatic, and environmental variations. Interestingly, notoungulates were mostly herbivorous and acquired high-crowned teeth very early in their evolutionary history. We focused on the variations in crown height, dental eruption pattern, and associated body mass of 69 notoungulate taxa, placed in their phylogenetic and geological contexts. We showed that notoungulates evolved higher crowns several times between 45 and 20 Ma, independently of the variation in body mass. Interestingly, the independent acquisitions of ever-growing teeth were systematically accompanied by eruption of molars faster than permanent premolars. These repeated associations of dental innovations have never been documented for other mammals and raise questions on their significance and causal relationships. We suggest that these correlated changes could originate from ontogenetic adjustments favored by structural constraints, and may indicate accelerated life histories. Complementarily, these more durable and efficient dentitions could be selected to cope with important ingestions of abrasive particles in the context of intensified volcanism and increasing aridity. This study demonstrates that assessing both life history and ecological traits allows a better knowledge of the specializations of extinct mammals that evolved under strong environmental constraints.

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Association between the Regulatory Locus PGM-1r* and Life-history Types of Juvenile Atlantic Salmon (Salmo salar)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f94-131 ◽

1994 ◽

Vol 51 (6) ◽

pp. 1322-1329 ◽

Cited By ~ 8

Author(s):

Susan M. Pollard ◽

Roy G. Danzmann ◽

Ross R. Claytor

Keyword(s):

Life History ◽

Atlantic Salmon ◽

Salmo Salar ◽

Regulatory Gene ◽

Fork Length ◽

Gonadal Development ◽

Gene Variant ◽

Atlantic Salmon Salmo Salar ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Accelerated Life

We sampled three juvenile life-history types of Atlantic salmon (Salmo salar) from Western Arm Brook, Newfoundland, to test whether a regulatory gene variant PGM-1r*b is associated with accelerated life-history development. Seven nonmigratory parr populations from the Miramichi River, New Brunswick, and the Margaree River, Nova Scotia, were also sampled. Previous studies with rainbow trout (Oncorhynchus mykiss) indicate that the liver-specific regulatory gene variant PGM-1r*b is associated with faster embryonic and life-history development. We found no association between variation at PGM-1r* and body weight, fork length, gonadal development, and smolt age. However, the frequency of PGM-1r* was significantly higher in males than in females for combined life-history types from Western Arm Brook. These results suggest that PGM-1r* is sex linked or under strong sex-specific selection in this population. Furthermore, populations with higher frequencies of PGM-1r*b tended to have higher frequencies of precocious maturation in males.

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Interrelationships of factors of social development are more complex than Life History Theory predicts

Behavioral and Brain Sciences ◽

10.1017/s0140525x19000177 ◽

2019 ◽

Vol 42 ◽

Author(s):

Boris Kotchoubey

Keyword(s):

Life History ◽

Social Development ◽

Life History Theory ◽

Strong Correlations ◽

Behavioral Features

Abstract Life History Theory (LHT) predicts a monotonous relationship between affluence and the rate of innovations and strong correlations within a cluster of behavioral features. Although both predictions can be true in specific cases, they are incorrect in general. Therefore, the author's explanations may be right, but they do not prove LHT and cannot be generalized to other apparently similar processes.

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