Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Chromosomes, reproductive biology, and developmental stages of Aponomma varanensis (Acari: Ixodidae).

Abstract

The tick A. varanensis attached to a king cobra (Ophiophagus hannah) was accidentally imported into the USA and was discovered at the Bronx Zoo in New York. Two generations of progeny were reared and investigated under laboratory conditions. Males had 21 chromosomes (20 autosomes and 1 sex chromosome). The processes of spermatogenesis and spermiogenesis were similar to those found in other ticks. However, the males are unusual in that timing of meiosis and spermatid production are not as synchronized among individuals as in other metastriate ticks, and they produce elongated spermatids without having a blood-meal. Although elongated spermatids were present in unfed males, they were not transferred to females off the host under the given experimental conditions. All stages of A. varanensis fed successfully on rat snakes (Elaphe obsoleta). Larvae also fed on eastern box turtles (Terrapene carolina), but not southern toads (Bufo terrestris), five-lined skinks (Eumeces fasciatus) or laboratory mice. Most of the A. varanensis behaved similarly to a typical 3-host tick and dropped from the host after each feeding, but about 3% of fed larvae remained attached and ecdysed on the host, and the resulting nymphs immediately began feeding. Unfed larvae were exceptionally long-lived (more than 22 months).