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Review
. 2018 Jan 15:10:1179543317751909.
doi: 10.1177/1179543317751909. eCollection 2018.

The Reproductive Morphology and Physiological Age Grading of the Female Salvinia Weevil, Cyrtobagous salviniae Calder and Sands

Lee Eisenberg  1 , Seth Johnson  1 , Michael J Grodowitz  2
Affiliations
Review

The Reproductive Morphology and Physiological Age Grading of the Female Salvinia Weevil, Cyrtobagous salviniae Calder and Sands

Lee Eisenberg et al. Int J Insect Sci. .

Abstract

The morphology of the female Cyrtobagous salviniae Calder and Sands reproductive system is similar to other weevil species being meroistic and telotrophic. The reproductive system is composed of 2 ovaries each containing 2 ovarioles where the follicles mature. A physiological age grading system was developed where the continuum of ovarium development was divided into 2 nulliparous and 3 parous classes. This was based on the differentiation of the ovarioles, presence, and appearance of follicular relics, cuticle hardness/coloration, and fat body quantity/appearance. High correlation occurred between the parous classes and number of eggs produced where the P3 class had over 9-fold higher number of eggs in comparison with the P1 class. Mean number of eggs produced for each parous class was significantly different, however, overlap occurred. Such a system enables a determination of the past, present, and future reproductive status of field populations and mass-rearing colonies.

Keywords: Water hyacinth; follicular relics; ovarian development.

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Conflict of interest statement

Declaration of conflicting interests:The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
(A) Ovarian morphology of female Cyrtobagous salviniae and (B) details of follicle morphology. co indicates common oviducts; fe, follicular epithelia; flc, follicle; fr, follicular relics; gm, germarium; gv, germinal vesicle; if, interfollicular tissue; lo, lateral oviducts; os, ovariole sheath; ov, ovaries; ovl, ovariole; tf, terminal filament; vt, vitellarium; yk, yolk.
Figure 2.
Figure 2.
Close-up of the follicular relics of Cyrtobagous salviniae. e indicates egg; flc, follicle; fr, follicular relics.
Figure 3.
Figure 3.
(A, B) The spermatheca of Cyrtobagous salviniae is a sclerotized pouch-like structure which houses the sperm until fertilization occurs. The cloudy material within the spermatheca is sperm. mb indicates muscle bands; spt, spermatheca; sptd, spermathecal duct; sptg, spermathecal gland.
Figure 4.
Figure 4.
The nulliparous classes of Cyrtobagous salviniae: (A) N1—note the reduced length and lack of ovariole differentiation, ie, no developing follicles present and (B) N2—ovarioles are differentiated with distinct follicles present. flc indicates follicle.
Figure 5.
Figure 5.
The parous classes of Cyrtobagous salviniae: (A) P1—follicular relics do not completely encircle the base of the ovariole, (B) P2—follicular relics encircle the base of the ovariole, (C) P3—dark particles or inclusions present in follicular relics apparently due to their compression from a high number of ovulations, and (D) degenerate ovaries; follicular relics dark, dark particles present and limited number of healthy follicles present. fr indicates follicular relics.
Figure 6.
Figure 6.
Mean number and range of ovulations/ovipositions for each parous age class for Cyrtobagous salviniae. Numbers above the min/max lines are the actual min/max values.
Figure 7.
Figure 7.
Correlation between mean weekly counts of number of eggs oviposited by Cyrtobagous salviniae (P < .05, r = .868, n = 20).
See this image and copyright information in PMC

References

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