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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #350597

Research Project: Management of Invasive Weeds in Rangeland, Forest and Riparian Ecosystems in the Far Western U.S. Using Biological Control

Location: Invasive Species and Pollinator Health

Title: The reproductive biology of Oxyops vitiosa Pascoe, 1870 (Colepotera: Curculionidae), a biological control agent of the invasive tree Melaleuca quinquenervia (Myrtaceae)

Author
item Pratt, Paul
item Grodowitz, Michael
item Center, Ted
item Rayamajhi, Min

Submitted to: Pan Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2018
Publication Date: 11/12/2018
Citation: Pratt, P.D., Grodowitz, M.J., Center, T.D., Rayamajhi, M.B. 2018. The reproductive biology of Oxyops vitiosa Pascoe, 1870 (Colepotera: Curculionidae), a biological control agent of the invasive tree Melaleuca quinquenervia (Myrtaceae). Pan Pacific Entomology. 94(3:117-129. https://doi.org/10.3956/2018-94.3.117.
DOI: https://doi.org/10.3956/2018-94.3.117

Interpretive Summary: The invasive tree Melaleuca quinquenervia (Cav.) Blake is widely distributed throughout peninsular Florida, USA and poses a threat to species diversity in the wetland systems of the Florida Everglades. Biological control research targeting the weed resulted in the introduction of Oxyops vitiosa Pascoe to Florida. Approximately three years following its release, adult weevils were collected over 12 consecutive months across six study sites, resulting in a 52:48 F:M sex ratio that did not vary among sites or over time. All female weevils were dissected and their reproductive anatomy was investigated, particularly in relation to the fluctuation of host plant suitability. The continuum of reproductive development was divided into three distinct stages: nulliparous, parous, or degenerative. The general anatomy of each stage is described. In contrast to other systems, fat body abundance provided little insight into the weevil’s reproductive status as 99.5% of all females possessed fat bodies that filled >2/3 of the abdominal cavity. Nulliparous weevils possessed the softest elytra and were lighter in color, parous weevils had the hardest and darkest elytra, while females with degenerated reproductive systems were intermediate to the other two reproductive classes. The proportion of parous O. vitiosa females in a population was strongly influenced by resource availability as the number of actively ovipositing females increased concomitantly with increasing suitable foliage in the host’s canopy.

Technical Abstract: The invasive tree Melaleuca quinquenervia (Cav.) Blake is widely distributed throughout peninsular Florida, USA and poses a threat to species diversity in the wetland systems of the Florida Everglades. Biological control research targeting the weed resulted in the introduction of Oxyops vitiosa Pascoe to Florida. Approximately three years following its release, adult weevils were collected over 12 consecutive months across six study sites, resulting in a 52:48 F:M sex ratio that did not vary among sites or over time. All female weevils were dissected and their reproductive anatomy was investigated, particularly in relation to the fluctuation of host plant suitability. The continuum of reproductive development was divided into three distinct stages: nulliparous, parous, or degenerative. The general anatomy of each stage is described. In contrast to other systems, fat body abundance provided little insight into the weevil’s reproductive status as 99.5% of all females possessed fat bodies that filled >2/3 of the abdominal cavity. Nulliparous weevils possessed the softest elytra and were lighter in color, parous weevils had the hardest and darkest elytra, while females with degenerated reproductive systems were intermediate to the other two reproductive classes. The proportion of parous O. vitiosa females in a population was strongly influenced by resource availability as the number of actively ovipositing females increased concomitantly with increasing suitable foliage in the host’s canopy.