Transmission, Host Specificity, and Seasonal Occurrence ofCyrtosomum penneri(Nematoda: Atractidae) in Lizards from Florida

Abstract

Experimental infections and field-collected lizards were used to investigate issues of transmission, host specificity, and seasonal occurrence in the nematode Cyrtosomum penneri (Cosmocercoidea: Atractidae). Anolis sagrei (87 males, 42 females) were captured from the Florida Southern College campus, Polk County, Florida, from October 2010 to September 2011, and 8,803 C. penneri were collected from their intestines. During the breeding season all sexually mature (SVL ≥ 34 mm) A. sagrei were infected, whereas juvenile lizards (SVL <34 mm) were never infected. Experimental infections, using A. sagrei , found that worms were transferred to new hosts venereally, but not during oral exposures. Mating trials confirmed that worms were consistently transferred between hosts during copulation under natural conditions. Experimental exposures found that land snails and crickets do not serve as transport or intermediate hosts, which supports the idea that C. penneri is transferred only during host copulation. Experimental infections to test host specificity in C. penneri successfully infected A. sagrei , Hemidactylus turcicus , and Sceloporus undulatus , but not Anolis carolinensis or Plestiodon inexpectatus. Overall, this is the first study to fully elucidate the life cycle of any atractid nematode, and we suggest a venereal route of transmission for all atractid worms that infect reptilian hosts. Our findings also have implications for the host's reproductive and behavioral biology, e.g., support for covert or satellite males in the A. sagrei mating system.

High infection intensities, but negligible fitness costs, suggest tolerance of gastrointestinal nematodes in a tropical snake

“…Although experimental transfer of adult nematodes is possible in reptiles (Langford et al . ), we cannot be confident that our attempt was successful.…”

Both sexes suffer increased parasitism and reduced energy storage as costs of reproduction in the brown anole,Anolis sagrei

“…The decrease in the prevalence of atractid nematodes that we observed in nonreproductive males and females also highlights the importance of sexually transmitted parasites as a frequently overlooked cost of reproduction (Hurst et al ., ; Lockhart, Thrall & Antonovics, ). To the extent that castration may have eliminated or reduced the frequency of copulation, castrated animals may have been sheltered from continued reinfection by atractid nematodes (Langford et al ., ). Although few sexually transmitted parasites are studied in wild populations, animals with high degrees of promiscuity and overlapping generations are particularly likely to harbour such parasites (Webberley et al ., ).…”

“…We stored the entire gastrointestinal tract in 10% formalin, then sectioned lower gastrointestinal tracts into 1‐cm pieces and counted the total number of rectal nematodes (Atractidae) in all sections under a dissection scope. Atractid nematodes are viviparous, undergo direct development in the lower intestine of their host, and have a venereal mode of transmission between individual hosts (Norval et al ., ; Langford, Willobee & Isidoro, ). For the same subset of animals, we dissected the stomach and counted all visible nematodes (Physalopteridae).…”

Silent pirates: Anolis sagrei Dum&eacute;ril &amp; Bibron, 1837 (Squamata, Dactyloidae) taking over Panama City, Panama

“…Therefore, there are populations living in small patches of bushes in gardens around big cities (Amador et al 2017). Anolis sagrei has fast reproductive cycle and ontogenetic development, females can lay an egg every 10 days, and one-month old juveniles may be reproductively mature (Lee et al 1989). Due to these fast reproductive cycles, colonizing new and urban areas should not be difficult for this species (Amador et al 2017, Tan and Lim 2012, Williams 1969.…”