Mortality, metabolic rate, and oviposition of Gryllus (Gryllus) assimilis (Fabricius, 1775) (Orthoptera: Gryllidae) females under constant and fluctuating warm temperatures

Boaventura Lobo Centeno Filho; Guilherme Martins Limberger; Kathellen Pintado Esteves; Duane Barros da Fonseca; Fábio Everton Maciel

doi:10.1016/j.jtherbio.2023.103574

Mortality, metabolic rate, and oviposition of Gryllus (Gryllus) assimilis (Fabricius, 1775) (Orthoptera: Gryllidae) females under constant and fluctuating warm temperatures

J Therm Biol. 2023 May:114:103574. doi: 10.1016/j.jtherbio.2023.103574. Epub 2023 May 4.

Authors

Boaventura Lobo Centeno Filho¹, Guilherme Martins Limberger¹, Kathellen Pintado Esteves², Duane Barros da Fonseca², Fábio Everton Maciel³

Affiliations

¹ Programa de Pós-Graduação em Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Rio Grande, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, 96203-900, Brazil.
² Instituto de Ciências Biológicas, Universidade Federal de Rio Grande, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, 96203-900, Brazil.
³ Programa de Pós-Graduação em Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Rio Grande, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, 96203-900, Brazil. Electronic address: maciel-fe@hotmail.com.

PMID: 37209634
DOI: 10.1016/j.jtherbio.2023.103574

Abstract

The global average temperature will increase by up to 5.7 °C, under high greenhouse gas emissions, consequently increasing the frequency of heatwaves, according to recent IPCC forecasts. These especially impacts ectotherms, such as insects, which are the most susceptible animals to changes in environmental temperature, affecting their physiology and reproduction. Thus, we investigated the effects of a 96-h exposure to constant temperatures (CT: 27, 30.5, 34, 39, 41, or 43 °C) and fluctuating temperatures (FT: 27/34 °C, 12/12 h) on the survival, metabolic rate, and oviposition of the female cricket Gryllus (Gryllus) assimilis (Orthoptera: Gryllidae). Mortality, body mass and water content of females and males were quantified and compared. It was found that CT₂₇, CT₃₄ and FT_27/34 do not cause mortality in females of G. (G.) assimilis. CT_30.5 (average temperature between 27 and 34), despite causing mortality of 5.0 ± 3.5%, do not differ from CT₂₇, CT₃₄ or FT_27/34. CT₃₉ causes a mortality of 8.3 ± 5.5%. Estimated lethal temperature for 50% of the population of females (LT_50Temp) is 40 °C, and 43 °C promotes 100% mortality in 96 h. Comparing mortality between sexes, females present higher LT_50Temp and thermotolerance than males. In addition, FT_27/34 and CT₃₄ do not differ in the metabolic rate, but both have higher values than CT₂₇. CT₃₄ strongly reduces oviposition in females, however FT_27/34 does not. We suggest that CT₃₄ reduces oviposition in females in two ways: by affecting the endocrine system related to egg production, or by causing behavioral egg retention, as a strategy to survive thermal stress. Moreover, females had a higher wet body mass and present a lower average weight loss than males. In conclusion, despite females present a higher mortality at temperatures above 39 °C, they are more thermotolerant than males. Furthermore, CT₃₄ is detrimental to the oviposition of G. (G.) assimilis.

Keywords: Fecundity; Heatwave; Thermotolerance; VCO(2); Water content.

MeSH terms

Animals
Female
Gryllidae* / physiology
Male
Oviposition
Reproduction
Temperature
Thermotolerance*