Differential impacts of ionizing radiation on a sexually dimorphic trait in male and female Acheta domesticus

Abstract

Purpose

In many Orthopteran species, including crickets, forewings exhibit substantial sexual dimorphism driven by sexual selection. In the cricket, Acheta domesticus, females are the ‘choosy’ sex and males exhibit multiple sexual signals to attract and successfully mate. Male forewings have highly specialized structures critical for acoustic signaling and mating. In contrast, female forewings currently serve no known purpose in this flightless species. Forewings also differ morphologically with male forewings containing complex acoustic producing and resonating regions and females lacking any defined structures. Due to their importance to mating as well as their structural complexity, impacts of environmental stress that target cricket forewing development may therefore have more severe consequences in males than females. Here, we investigate the sensitivity of a sexually dimorphic trait, forewing morphology, to an early life environmental stressor.

Materials and Methods

We applied ionizing radiation (0-–27.8 Gy) as a stressor as dose can be precisely applied as well as its relevance in both environmental contamination and use in the Sterile Insect Technique.

Results

A canonical variate analysis indicated that wing shape was significantly altered in males at all doses; .58 Gy, 2.3 Gy, 4.6 Gy, 16.2 Gy, and 23.2 Gy. In females, shape was significantly altered at 27.8 Gy and 23.2 Gy groups and to a lesser extent at .58 Gy and 16.2 Gy. Linear regression analysis of centroid size indicated a dose dependent decline in wing size in both sexes, with males exhibiting more decline. Fluctuating asymmetry, a measure of environmental sensitivity, revealed that males were more sensitive to shape changes due to stress than females. This difference in sensitivity is likely due to the complexity of male forewings.

Conclusion

These results expand understanding of sex dimorphism in stress responses and sensitivity to ionizing radiation.

Keywords:

• Ionizing radiation
• wing morphology
• development
• sexual dimorphism
• sexual selection
• crickets
• orthoptera

Disclosure statement

Authors have no competing interests to disclose.

Additional information

Funding

This work was funding by the NSERC Discovery Grant (RGPIN-05693-2015).

Notes on contributors

Tamara M. Fuciarelli

Tamara Fuciarelli: Tamara Fuciarelli is a current PhD candidate at McMaster University, Canada. She focuses on radiation impacts on the reproduction with a focus on generational effects using the House Cricket model. Having completed her M.Sc in 2019 she aims to further the field in radiobiology as it pertains to ecological impacts.

Selvi Patel

Selvi Patel: Selvi Patel is a recent 2022 graduate of McMaster University, Canada. She completed for undergraduate thesis focusing on radiation induced impacts on secondary sexual characteristics in House Crickets with a focus on sex differences. She aims to further the field in radiobiology as it pertains to ecological impacts.

C. David Rollo

Dr. David Rollo: David Rollo is an environmental physiologist employed at McMaster University, Canada. He is a well-known researcher in the study of stress and aging and has published several landmark studies on the subject. His current research focuses on the integration and functions of behavior, morphology and physiology in response to environmental stress. He examines adjustments of the above features using ionizing radiation as a precise stressor using a cricket model. A short-lived animal allows for the study of lifetime and trans-generational impacts on life history features, behavior, physiology, and aging. For reproduction, he focuses on sexual signaling (chemical and acoustic) and mating behavior. Trans-generational studies of irradiation focus on life history traits, transmission of stress resistance, fertility, and social recognition. Key aspects of current interest include feeding and thermal choices, cognition, reproduction, growth, immunology, avoidance of death cues, aging and longevity.