The pattern of reproduction in the mole-ratHeliophobiusfrom Tanzania: do not refrain during the long rains!

Abstract

The genus Heliophobius Peters, 1846 comprises at least six cryptic, topotypical species in the Heliophobius argenteocinereus Peters, 1846 species complex. The current study investigated the breeding patterns of a wild-caught population from Tanzania where the putative species Heliophobius argenteocinereus emini Noack, 1894 resides. Individuals were collected on a monthly basis for an entire calendar year. Assessment of fœtus presence, gonadal histology, reproductive-tract morphometrics in combination with gonadal steroid (plasma progesterone and œstradiol-17β in females and testosterone in males) measurements and field observations revealed that rainfall is important for the onset of breeding. The results further confirmed that breeding is limited to a single, yearly reproductive event synchronised to the long rainfall pattern. The distinct breeding peak in July is associated with an elevation in gonadal mass, increase in concentrations of reproductive hormones, and presence of Graafian follicles and corpora lutea in the ovaries of females. These reproductive parameters coincided with the end of the long rainfall period, whereas presence of young in the maternal burrow system corresponded with the start of the short rainfall of East Africa. These findings confirm Heliophobius has a single breeding opportunity each year, and this species is therefore vulnerable to any changes that may impact their climatically attuned breeding patterns.

Reproductive status‐dependent kisspeptin and RFamide‐related peptide (Rfrp) gene expression in female Damaraland mole‐rats

“…Blood samples were centrifuged, the plasma collected and frozen at −40°C until the hormone assay was conducted. The oestradiol 17β assay was performed as described previously using the Coat‐a‐Count MG 12101 oestradiol kit (IBL International GmbH Hamburg, Germany). The cross‐reactivity of the antibody to all naturally occurring steroids was 10% with oestrone, < 5% with oestriol, oestrone‐β‐ d ‐glucoronide, oestrone‐3‐sulphate, d ‐eequilenin, 17β oestradiol‐3‐monosulphate, testosterone and androsterone.…”

Ecophysiology of mammals

“…Subterranean coruros (Spalacopus cyanus) increase ventilation when exposed to hypoxia, while fossorial degus (Octodon degus) do so in response to hypercapnia (Tomasco et al 2010). Much fossorial mammal research is on mole-rats, which have seasonal cycles in activity and reproduction, apparently related more to rainfall than to temperature (Heliophobius argenteocinereus- Zelová et al 2011;Ngalameno et al 2017), and extremely long life-spans (Heterocephalus glaber- Kim et al 2011).…”

Pattern of ovulation in an ancient, solitary mole-rat lineage:Heliophobius argenteocinereus eminifrom Tanzania

“…Heliophobius a. Emini breeds seasonally with a clear single breeding cycle of one litter per annum (Šumbera et al 2003a;Ngalameno et al 2017). Heliophobius a. emini They exhibit lower concentrations of steroid hormone and reduced gonadal size from September through to early May with pups born from the end of August to October, signifying that mating occurs towards the end of May (Šumbera 2003a;Ngalameno et al 2017).…”

“…Heliophobius argenteocinereus emini is a seasonal breeder with reproduction closely linked to the latter part of the long rains (Šumbera et al 2003;Ngalameno et al 2017). Reproduction is restricted to a single breeding event per year with a litter size that ranges from 3-6 per adult female.…”

“…Reproduction is restricted to a single breeding event per year with a litter size that ranges from 3-6 per adult female. Reproductive activity arises during the middle of the long rains with birth peaking at the end of the long rainy season (Šumbera et al 2003a;2008;Ngalameno et al 2017).…”