Slack / Private Message Drop — page 828

[2021-05-17 17:12:11] [Kristian Andersen] That's exactly right. We should probably involve him in this little project too - they have been looking pretty carefully at the early events and I know he's been doing some studies to show that there are no signs of culture adaptation. [2021-05-17 17:27:59] [Eddie Holmes] This from Alice. She's a bat ecologist who actually lives and works in Yunnan: "In Mid-Northern Yunnan Rhinolophids hibernate, down in the tropics we have not found hibernacula, but the numbers we capture go right down so they are either using different areas or inaccessible hibernacula-there is always some activity though, so at least some individuals in South Yunnan never hibernate, some may-but only for a very short period." [2021-05-17 17:31:30] [Kristian Andersen] Do they migrate at all or move around for any of these events? I'm wondering if there's some sort of connection between the winter months and the virus getting into contact with intermediate hosts. HKU-1 also happened in the winter - probably January. [2021-05-17 17:36:51] [Eddie Holmes] I'll check. [2021-05-17 18:17:00] [Eddie Holmes] More from Alice. I asked here in there might be more opportunities for cross-species transmission during Nov-Jan. [2021-05-17 18:17:05] [Eddie Holmes] "It's complicated. Many bats have maternity roosts, so there is sexual segregation for certain parts of the year during breeding, in China that period will vary, but we see most females starting to give birth in late April-May. They will then nurse their baby (typically one) for a number of months, and the Rhinos will leave young in a "creche" during foraging, whereas some other species will often feed whilst carrying their young. Those activities are finished by November, but at least some species have the mating period then (most species have delayed implantation, or delayed fertilisation etc capabilities). The Rhino's are very polygamous with very scewed success ratios, so a minority of males mate with all the females (there is paternity data for some colonies, and some males have many tens of offspring in a year whereas others have none). Other taxa have different patterns, in Hipposiderids, especially larger species males may fight and they have enlarged glands and are exceedingly aggressive (normally on the face, though some other genera within Hipposideridae have them elsewhere-such as the chest). Following from this there is a shift in cave use, Hipposiderids show evidence of migration in some species within China-we see them appearing for a small period of the year and their morphology and habitat use means they are able to move long distances and are almost certainly migratory (for at least larger species, smaller species like Aselliscus will hibernate, and actually go into a much deeper daily torpour even at moderately low temperatures). Rhinolophids clearly also change roosts then, possibly choosing deeper, more thermally stable caves. So that period of the year is basically pretty high stress, most species will be changing roosts, so there are different communities, less sexual segregation than the rest of the year, lower food (so physical stress). This period is also when fungal pathogens like whitenose syndrome appear-so it is likely that during torpour they may be downregulating the functions that allow various pathogens to stay at lower levels and it may be that viral load would be higher at this time. In a disturbed cave, with higher stress this is likely to increase, they are also more likely to leave the cave in such conditions, which of course increases the interface for spillover to occur. -Rhinos and Hippos are sister groups, so may share traits, and in some cases roost in close proximaty, during cooler periods and hibernation smaller species may cluster to roost together, so there is also a potential for spillover between taxa there-though largely in the smaller species (larger Rhinolophids are solitary and rarely use large or communal caves, and large Hipposiderids are too aggressive)." [2021-05-17 19:00:29] [Robert Garry]