Research into mosquito larvae in pitchers

[Charles]

Hi Everyone,

I joined the forum earlier today (see introductions) and mentioned that I am starting up a number of research projects on Nepenthes at Monash University in KL, where I work. One of these projects developed from a presentation that I gave at the Penang flower show last year with Ch'ien Lee. I can't remember who it was, it might have been David Goh from the Butterfly House (please correct me if I'm wrong), but someone asked me whether vector mosquitoes breed in pitchers. My answer was "no, they don't", but he mentioned that he had been fined at least once by the local council in Penang for having mosquitoes breeding in his pitchers.

This made me realise: either we scientists could be wrong when we say that vector mosquitoes don't breed in pitchers, or the council could be wrong when they penalise growers for having harmless mosquito larvae in their pitchers (FYI, a vector mosquito is a species that transmits diseases such as dengue or malaria). Whatever the case, this is a matter that needs to be looked into, (a) so that you guys don't have to worry about getting fined if mosquitoes breed in your pitchers or (b) if there is a problem, we can find a way for you to easily and economically eliminate any risks, so you don't get into trouble. So, I applied for some research funds to investigate this and was fortunate enough to be successful.

The project will have two main parts. One of these will be laboratory-based and will involve several research students. They will look into the ability of Aedes albopictus mosquito larvae (the vector for dengue fever) to survive in pitchers. For this research, we would like to borrow some plants from any of you who might be interested in helping us out. We have a good horticultural facility here, so any plants we borrow will be well looked after. Plus, long before I became a scientist, I grew neps for a hobby, so I know how to look after them. We don't know how many plants, or what species we need, or how long we need them for yet, but I suspect that local lowland species from Peninsular Malaysia will be our first priority (mirabilis, gracilis, ampullaria, rafflesiana, albomarginata), along with some common horticultural hybrids. We're not after anything weird, rare or highland. I'll post another message on this topic in a few weeks' time - once the students are ready to start their projects.

The second part of the project will be run by me and what I would like to do is get a group of at least 3-4 growers together who have a lot of Nepenthes (i.e., nursery owners or the bigger collectors). Ideally, these people would live in KL and Penang, plus somewhere in east Malaysia, like Kuching or KK. I would like to work with this group to monitor every instance in which mosquitoes breed in their pitchers. Hopefully, this should be a very rare event and will not be time consuming for anyone, but it will enable us to find how often this happens and which mosquito species are involved. Chances are, virtually all of the mosquitoes will be harmless, but it would be nice to know for sure, wouldn't it? I'd like to get this part of the project up and running by late July, so if any of your are interested in participating, please let me know.

One thing I would suggest to anyone who is interested in this project: please don't try it at home! If you find Aedes larvae breeding around your home, don't put them in your pitchers, just destroy them. Messing with wild Aedes larvae could result in you getting dengue, which I'm told is not a lot of fun. There were over 50000 cases and 112 dengue-related deaths in the Klang Valley last year.

Thanks for hearing me out, and I hope to hear from some of you soon.

Cheers,

Charles

[NepNut]

Hi Charles,

This is a research that will benefit all, whaterver the finding/conclusion may be.

I would like to point out that there's been some recent outbreak of another deadly disease known as Chikungunya in Southern Thailand and Northern Peninsular Malaysia. Chikungunya is also transmitted by vector mosquitos like Aedes.

I hope you will find a definitive answer for your hypothesis. Good luck.

[piscesilim]

Very interesting project. Can't wait to know the result! But only Aedes consider as vector? How about Culex?

[Charles]

Yeah, good point, but we have to take things one step at a time. We know that Anopheles are super-rare in Nepenthes pitchers, if not completely absent. We also know that a lot of the mosquito species that normally colonise pitchers are Culex species. This means that investigating Culex in pitchers and their potential role as vectors will be more complicated and will require students who can identify/distinguish closely related mosquito species. We don't have any of those at Monash at the moment! Aedes/dengue appears to be the main arbovirus problem in urban areas in Malaysia at this time and it's the easiest to work with, so that's where we'll start.

Cheers,

Charles

[TranMinh]

Hi Charles,
I can see some mosquito larvae in my picher too. I don't know why ants, mouse get eat by acid water in picher. But mosquito larvae doesn't get kill ?

[Charles]

Hi TranMinh,

There are quite a few mosquito species whose larvae live in pitchers. Most of these are specialists that do not live anywhere else. These species are also thought to be harmless. We do not know exactly how they can survive in pitchers, but the only thing that is likely to have an effect on them is the acidity of the fluid. However, many animals can resist acids and enzymes while they are alive - it is only when they die and their bodies start to break up that they get digested. As far as we know, there are no strong patterns between fluid acidity and numbers or diversity of mosquitoes in pitchers, so it seems that most of these animals are well-adapted to life in pitchers.

Do you have wild Nepenthes growing close to where you live? This is something we are interested in investigating, because we'd like to find out where the mosquitoes are coming from.

Cheers,

Charles