Endocrine regulation of reproduction and diapause in the boll weevil, Anthonomus grandis Boheman

Taub-Montemayor, Tina E.; Palmer, James O.; Rankin, Mary Ann

doi:10.1002/(sici)1520-6327(1997)35:4<455::aid-arch8>3.0.co;2-q

Cited by 12 publications

(6 citation statements)

References 44 publications

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“…Surprisingly, low levels of AgraVg transcripts were detected in eggs, larval and pupal stages. Other work did not mention the presence of either AgraVg transcripts or proteins in other stages than adult female in A. grandis ( Taub-Montemayor et al, 1997a , Taub-Montemayor et al, 1997b , Taub-Montemayor and Rankin, 1997 ). Only very low transcript amounts were detected in comparison to adult females, representing maybe just basal transcription ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Vitellogenin knockdown strongly affects cotton boll weevil egg viability but not the number of eggs laid by females

et al. 2016

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Vitellogenin (Vg), a yolk protein precursor, is the primary egg nutrient source involved in insect reproduction and embryo development. The Cotton Boll weevil (CBW) Anthonomus grandis Boheman, the most important cotton pest in Americas, accumulates large amounts of Vg during reproduction. However, the precise role of this protein during embryo development in this insect remains unknown. Herein, we investigated the effects of vitellogenin (AgraVg) knockdown on the egg-laying and egg viability in A. grandis females, and also characterized morphologically the unviable eggs. AgraVg transcripts were found during all developmental stages of A. grandis, with highest abundance in females. Silencing of AgraVg culminated in a significant reduction in transcript amount, around 90%. Despite this transcriptional reduction, egg-laying was not affected in dsRNA-treated females but almost 100% of the eggs lost their viability. Eggs from dsRNA-treated females showed aberrant embryos phenotype suggesting interference at different stages of embryonic development. Unlike for other insects, the AgraVg knockdown did not affect the egg-laying ability of A. grandis, but hampered A. grandis reproduction by perturbing embryo development. We concluded that the Vg protein is essential for A. grandis reproduction and a good candidate to bio-engineer the resistance against this devastating cotton pest.

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Section: Discussionmentioning

confidence: 99%

Vitellogenin knockdown strongly affects cotton boll weevil egg viability but not the number of eggs laid by females

et al. 2016

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“…Some researchers have conjectured that feeding on bolls induces diapause in boll weevils (Lloyd et al., 1964, 1967; Graham et al., 1979), which, if true, could conceivably have influenced the results of this study. In this study, however, newly emerged, unfed female boll weevils were used and even those that consumed post‐bloom and young boll rinds or reproductive portions became gravid and had shorter longevities than square‐fed weevils, which fails to agree with the definition of diapause (Taub‐Montemayor et al., 1997) and the diapause characters set forth by Brazzel & Newsom (1959). Other experiments have shown that boll‐feeding does not necessarily induce diapause (Lloyd et al., 1967; Cobb & Bass, 1968; Spurgeon & Esquivel, 2000).…”

Section: Discussionmentioning

confidence: 98%

Longevity and egg development of adult female boll weevils fed exclusively on different parts and stages of cotton fruiting bodies

Showler¹

2008

Entomologia Exp Applicata

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The capacities of the rind (i.e., the developing calyx and petals of squares; and the outer casing, or husk, of bolls) and the internal reproductive portion of cotton, Gossypium hirsutum L. (Malvaceae), squares of three sizes, and bolls of three ages to influence adult female boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), longevity and egg production were evaluated in laboratory bioassays. While feeding on the reproductive portion of squares was expected to support adult boll weevils for considerable periods of time (e.g., medium square reproductive portion: ≈185 days), feeding on rinds also resulted in substantial longevity (e.g., medium square rind: ≈120 days). As anticipated, feeding on the reproductive portion of squares resulted in formation of chorionated eggs in mated females, but a diet comprised exclusively of rinds, particularly from large squares, was associated with gravidity and high fecundity relative to rinds of young and mature bolls. The reproductive portion and rind of post‐bloom and young bolls as sources of food resulted in limited gravidity while mature bolls were not associated with any egg formation. These findings further our understanding of how boll weevils feed on different parts of the cotton plant and how those parts as food sources are related to the biology and ecology of the boll weevil.

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“…A similar decrease in feeding rate was observed in naturally ovipositing females [ 21 ]. The artificially applied methoprene presumably acted like JH to stimulate egg maturation of diapausing females of C. basicorne , which enabled them to lay eggs [ 27 , 31 , 36 , 50 ].…”

Section: Discussionmentioning

confidence: 99%

“…Reproductive diapause of insects is generally regulated by two hormones: juvenile hormone (JH) secreted from the corpora allata (CA) and ecdysone secreted from both the prothoracic gland in larval stages [ 7 , 22 ] and reproductive organs including the ovaries of females and accessary glands of males [ 23 , 24 ]. Reduced JH titer induces reproductive diapause [ 25 , 26 ], which is caused by either JH esterase activity [ 27 , 28 ] or blocking the JH biosynthesis pathway [ 29 ]. Further, 20-hydroxyecdysone (20E), which is the active form of ecdysone, is necessary for JH production and terminating reproductive diapause [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Topical Application of Synthetic Hormones Terminated Reproductive Diapause of a Univoltine Weed Biological Control Agent

Park

Smith

2021

Insects

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Classical biological control is an important method for controlling invasive alien weeds. Univoltine insects can be highly effective biological control agents of annual weeds because they are well synchronized with their host plant. However, having only one generation per year makes it difficult and slow to multiply them in the laboratory for initial field releases. If it were possible to terminate reproductive diapause early, then we could rear multiple generations per year, which would greatly increase annual production. We used a recently approved biocontrol agent, Ceratapion basicorne (a univoltine weevil), for yellow starthistle (Centaurea solstitialis) as a model system to study the use of two insect hormones, 20-hydroxyecdysone (20E) and methoprene, to terminate reproductive diapause. Methoprene (1 μg applied topically) terminated reproductive diapause of female weevils, whereas doses of 0.0, 0.01 and 0.1 μg did not. The combination of methoprene and 20E had a stronger effect and induced an increase in eggs (1.51 ± 0.16 eggs/day, mean ± SE) compared with a methoprene only group (1.00 ± 0.13 eggs/day), and a control group (0.21 ± 0.04 eggs/day). Thus, topical application of these hormones should enable us to rear the weevil out of its normal season and produce more than one generation per year, which will increase productivity of mass-rearing it for field release. Once released in the field, the insect would continue as a univoltine agent that is well-synchronized with its host plant.

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Endocrine regulation of reproduction and diapause in the boll weevil, Anthonomus grandis Boheman

Cited by 12 publications

References 44 publications

Vitellogenin knockdown strongly affects cotton boll weevil egg viability but not the number of eggs laid by females

Vitellogenin knockdown strongly affects cotton boll weevil egg viability but not the number of eggs laid by females

Longevity and egg development of adult female boll weevils fed exclusively on different parts and stages of cotton fruiting bodies

Topical Application of Synthetic Hormones Terminated Reproductive Diapause of a Univoltine Weed Biological Control Agent

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