Reproductive biology of the onychophoran Euperipatoides rowelli

Abstract

The reproductive biology of the ovoviviparous peripatus Euperipatoides rowelli was investigated from ®eld collections and laboratory cultures. The sexes have different demographics. The frequency distribution of individual weight is essentially L-shaped in females, but closer to normality for males: thus the sexes must exhibit different patterns of growth and/or mortality. Males are generally much smaller and rarer than females. The primary sex ratio seems to be 1:1 with equal investment in the sexes, while the tertiary ratio is highly female-biased. Logs with fewer individuals tend to be male-biased while well-populated logs tend to be female-biased. Males mature at 15±30% of the bodyweight of mature females. The weight frequency distribution of males without developed sperm in their tracts is strongly skewed to the lower weights, while that of males with sperm is more normally distributed, indicating that sperm production occurs as soon in life as possible. Males mature in their ®rst year of life, if growth rates in culture may be extrapolated to the wild. In contrast to this rapid maturity in males, females may mature as late as their second or third years. Most mature females, and many prior to maturity, carry sperm in their spermathecae. After maturity, there is an approximately linear relationship between body mass and number of developing embryos. Reproduction in E. rowelli is signi®cantly seasonal despite high individual variance, with a major bout of parturition in November±December (summer). A female can harbour one developed and one undeveloped batch of embryos in each uterus. Excesses of developed embryos in one uterus are counterbalanced by de®cits of undeveloped ones, indicating that females can use their paired reproductive tracts independently. Individual females in culture can experience episodes of parturition approx. 6 months apart without re-mating, thus gestation may be 6 months or more. Sperm in spermathecae remain capable of vigorous swimming for at least 9.5 months.

Phylogenetics of Planipapillus, Lawn-Headed Onychophorans of the Australian Alps, Based on Nuclear and Mitochondrial Gene Sequences

“…Gleeson et al (1998) found that high levels of intraspecific COI variation also characterize Ooperipatellus insignis (11%) and Peripatoides novaezealandiae (7%). These taxa most likely represent species complexes, as has proved true for many widespread onychophoran taxa (Trewick, 1998(Trewick, , 1999(Trewick, , 2000Reid, 1996;Reid et al, 1995;Briscoe and Tait, 1995;Sunnucks and Wilson, 1999).…”

“…Tissue was repeatedly soaked in TE9 buffer (Shiozawa et al, 1992) for several hours to leach pigments, which may act as PCR inhibitors (Sunnucks and Wilson, 1999). Tissues were then homogenized in 250 l TE9 and incubated overnight at 65°C after the addition of 30 l 20% SDS and 5 l 10 mg/ml proteinase K. Protein was precipitated with ammonium acetate, and DNA was precipitated from the supernatant with ethanol.…”

Onychophora

“…Dashed branches indicate putative position of key taxa missing in the analysis of Murienne et al ( 2014 ). * This mode might in fact be combined lecithotrophic/matrotrophic viviparity, which has been shown to exist in Euperipatoides rowelli (see Sunnucks et al 2000 ). " + " and " -" at each node indicate, respectively, the presence/absence of the vitelline envelope ( left ) and the chorion ( right ); question marks indicate missing data.…”

Head development in the onychophoran Euperipatoides kanangrensis with particular reference to the central nervous system

“…These embryos are often in two batches of different developmental stages: the batch closer to the ovary is at an earlier developmental stage than the batch closer to the genital opening. The reproductive biology of a closely related species is reported in Sunnucks et al (2000). The embryos were dissected out and, after removal of the egg membranes, fixed in a mixture of 1.5% paraformaldehyde and 1.5% glutaraldehyde in 0.1 M phosphate buffer, pH 7.4, for scanning electron microscopy (SEM), transmission electron microscopy (TEM), and light microscopy (LM).…”