Are There Downsides for Boll Weevils in Dry Cotton Bolls?

Jenn Hoskins
11th July, 2024

Are There Downsides for Boll Weevils in Dry Cotton Bolls?

Image Source: Natural Science News, 2024

Key Findings

  • The study was conducted in Bahia, Brazil, focusing on boll weevils from different environments: dry bolls, squares, and traps
  • Boll weevils from dry bolls showed higher reproductive potential and longevity compared to those from squares and traps
  • Weevils from dry bolls were larger in size, which is linked to their higher reproductive success and longevity
The boll weevil, Anthonomus grandis grandis, is a notorious pest that significantly impacts cotton production across the Americas, with potential to spread to other continents. This insect relies heavily on the reproductive organs of cotton plants for feeding, laying eggs, and survival during the off-season by sheltering in dry bolls. A recent study conducted by the Universidade Estadual do Sudoeste da Bahia aimed to investigate the reproductive potential, feeding behavior, longevity, and morphometric characteristics of boll weevils sourced from different environments: dry bolls, squares (flower buds), and traps[1]. The study involved collecting adult boll weevils from infested squares, dry bolls, and traps placed in cotton fields and the Caatinga area. Thirty pairs of these weevils were then maintained in a laboratory setting to monitor their oviposition (egg-laying), feeding behavior, longevity, and various morphometric measurements (physical attributes) across both the parental and first-generation (F1) weevils. One of the critical findings from this study was the significant variation in reproductive potential and feeding behavior among weevils from different sources. Weevils emerging from dry bolls demonstrated a higher reproductive potential and longevity compared to those from squares and traps. This aligns with earlier observations that weevils tend to settle on cotton bolls in the lower parts of the plant, potentially minimizing their exposure to insecticide residues[2]. The study also found that the feeding holes created by weevils from dry bolls were more numerous, indicating a higher feeding activity which supports their increased reproductive output. Interestingly, the study's morphometric analysis revealed that weevils from dry bolls were generally larger than those from squares and traps. This finding is consistent with the theory that larger body size correlates with higher reproductive rates, although metabolic constraints can sometimes impede this relationship[3]. The larger size and greater energy reserves of these weevils likely contribute to their enhanced reproductive success and longevity. Additionally, the study sheds light on the adaptive strategies of boll weevils, particularly their ability to enter a reproductive dormancy during the off-season. This dormancy is crucial for their survival and successful colonization of cotton fields in subsequent seasons. Previous research has shown that boll weevils can enter facultative reproductive dormancy, with food sources and field conditions playing a decisive role in this process[4]. The current study supports these findings, highlighting the importance of understanding the ecological and physiological factors that influence boll weevil behavior and reproduction. The implications of these findings are significant for developing more effective pest management strategies. Current challenges in controlling boll weevils include their within-plant distribution, which minimizes contact with insecticide residues, and their low susceptibility to commonly used insecticides like malathion and pyrethroids[2]. By understanding the reproductive and feeding behaviors of weevils from different sources, researchers and farmers can better target their control measures to reduce the pest population more effectively. In conclusion, the study by the Universidade Estadual do Sudoeste da Bahia provides valuable insights into the reproductive potential, feeding behavior, longevity, and morphometric characteristics of boll weevils from various sources. These findings contribute to a deeper understanding of the adaptive mechanisms that enable boll weevils to thrive in diverse environments, ultimately aiding in the development of more effective pest management strategies.

AgricultureEnvironmentAnimal Science

References

Main Study

1) Boll weevils in dry bolls: is there a performance disadvantage?

Published 10th July, 2024

https://doi.org/10.1186/s42397-024-00186-x

Related Studies

2) Dispersal of boll weevil toward and within the cotton plant and implications for insecticide exposure.

https://doi.org/10.1002/ps.6148

3) Intraspecific variation in body size and the rate of reproduction in female insects - adaptive allometry or biophysical constraint?

https://doi.org/10.1111/j.1365-2656.2012.02010.x

4) Reproductive dormancy in boll-weevil from populations of the midwest of Brazil.

Journal: Journal of economic entomology, Issue: Vol 106, Issue 1, Feb 2013


Related Articles

An unhandled error has occurred. Reload 🗙