Research into mosquito larvae in pitchers
 

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

Re: Research into mosquito larvae in pitchers
 

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.

Re: Research into mosquito larvae in pitchers
 

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

Re: Research into mosquito larvae in pitchers
 

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

Re: Research into mosquito larvae in pitchers
 

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 ?

Re: Research into mosquito larvae in pitchers
 

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

Re: Research into mosquito larvae in pitchers
 

Hi Charles,
Thank for taking the time to answer. I'm live in VietNam, Ho Chi Minh City a round of the city is 10 - 14 river. A lot of mosquitos here, mosquito can be the mosquito make a thousand of people sick every year. So every time I saw it I will remove the water in picher or soon the larvae will become mature mosquito. I closer place to find nepenthes are Binh Chau hot sping, but most of nepenthes in that place have destroy my hot sping company, so hard to find it now. Binh Chau suround by 4000 hm2 of forest, find nepenthes is hard.

Re: Research into mosquito larvae in pitchers
 

Hi Charles,

newly open pitchers have extremely high enzyme vicosity . At this stage most small animals and insects will be suffocated, drown and die(?) . The vicosity diminishes as the pitchers aged and being diluted by rain water. Maybe(?) when the enzymes were completely diluted and displaced by water and only at this stage can mosquitoes have the freedom to lay eggs.

can you elaborate the vicosity of enzymes at different stages, in your past studies if any.

regards,
Robert

Re: Research into mosquito larvae in pitchers
 

Hi Robert,
Most of nepenthes mouth os hide by the lid ( except some species like Ampullaria, Lowii, .... ) but my Nepenthes rafflesiana have a few of mosquito larvae ( I have remove the water because mosquito larvae ) I think the mosquito larvae must have some think like skin to protech it from enzyme and acid.
Best regards,
Tran Minh.

Re: Research into mosquito larvae in pitchers
 

Hi Tran Minh,
in newly opened pitcher the enzymes are sticky like our saliva ( more or less except it is more watery ). However thick the larvae skin nothing can swim or dive in the extreme high viscosity...they call for help,nobody come to their rescue..hee.hehee

Re: Research into mosquito larvae in pitchers
 

Hi All,

It's nice to see that this discussion is going somewhere, and that several of you find it interesting. The constituents of Nepenthes fluid are still pretty much a mystery though. While nobody can be sure, the viscosity of the fluid in newly opened pitchers does not seem to be due to enzymes. In the few occasions when enzymes have been isolated from pitcher fluid, they are present in very small amounts. Current thinking suggests that the viscosity is more likely to be due to polysaccharides, which are common in plant-produced mucilage (but there's no proof yet). There was a recent paper that studied the trapping capabilities of the fluid due to its high viscoelastic properties (I can't remember the details at the moment, but tell that to your friends who grow sundews!). Trouble is, this is quite difficult to measure without sophisticated equipment. However, we are slowly finding out lots of new things about how Nepenthes pitchers work and no doubt the properties of the fluid will be investigated in detail in the near future.

In some work I did in Brunei in the early 1990's, the first mosquito larvae colonised the pitchers within 2-3 days of them opening, so the fluid viscosity per se is not an obstacle for some species. However, some other species only colonise pitchers that have been open for 40 days or more, so obviously there is some link between pitcher age and "suitability" for these species. Over the next 3-4 years, I hope to get quite a few students doing projects that will investigate a number of these things.

I'm really interested in what you guys find in your cultivated pitchers - from an ecologist's point of view, your pitchers represent an empty (but very specialised) habitat and we can learn a lot from the things you see in your gardens! In the last 2-3 years there has been a quiet revolution in our understanding of how Nepenthes pitchers function, and there is a great deal more new information just around the corner. It's an exciting time, but the downside is the the info comes through slowly and occasionally in scientific journals, so we all have to be patient.

Cheers,

Charles

Re: Research into mosquito larvae in pitchers
 

I think the water inside the pitcher is just somekind of water with fetilzer from the vitim. Nothing can kill but be drown. If the animal can swim then it can live there. Will try by put some some fish in my truncata's pitchers.
Dear all
Lamde83

Re: Research into mosquito larvae in pitchers
 

Wow lamede isn't that a bit cruel?? Maybe some frog lar xD

Re: Research into mosquito larvae in pitchers
 

how can a frog can get into the pitcher ? and how the young frog to get out of there ? :D just thinking ! kidding

Re: Research into mosquito larvae in pitchers
 

Maybe really drown then can dissolve or something like that?

Re: Research into mosquito larvae in pitchers
 

I had lizards in my miranda couple of times

Re: Research into mosquito larvae in pitchers
 

after some observation lately, i found mozzi larvae do survive in sarracenia purpurea sp purpurea, they hatch from the eggs till it turns into mozzi flying off in the pitcher

Re: Research into mosquito larvae in pitchers
 

Jus wanted to add my observation. I accidently spilled half my pitcher contents from my n. xDyeriana and together with a hundred dead ants :smile: there was about half a dozen mosquito larvae. The pitcher is nearly one and a half month old with the peristome starting to blacken off. I noticed that the mosquito larvae were quite small and sluggish, unlike the ones I commonly see in normal water. Also, they were very transparent with faded stripes at its back(abdomen). Worth noting also that there were no huge larvae at 1cm in length which leads me to guess that these larvae are slow growers.

Also, how's the research, Mr. Clarke? It's nearly a year since the last post and I really like to know the progress and what we will learn about the mosquito larvae in pitchers.

Re: Research into mosquito larvae in pitchers
 

The research has gone really well, thanks. We're in the process of analysing the data now, and hope to publish some of our findings later in the year. However, we had to change the scope of the project quite a lot. Our initial plan was to look at cultivated plants in collectors' gardens/greenhouses, but as we only got one firm offer of co-operation (everyone else went to ground when the time came to commit to the project!), we had to switch our project to looking at wild plants. However, this turned to be a very good "Plan B" and we now have a PhD student looking at this subject in more detail.

Cheers,

Charles

Re: Research into mosquito larvae in pitchers
 

Thats good! I can't wait for a published report! :1thumbup: good luck!

Re: Research into mosquito larvae in pitchers
 

I'll certainly let you know when we publish anything in this area. Our results are very interesting (to us, at least!), but as the work has been done by research students under my supervision, it is their data to publish (or not), so all I can do is gently coerce them to write it up! We have enough data for about 15 journal articles at the moment. Chances are, not all of this will get published, but even those results that do end up in print will take some time... it's just the way of the academic world.

Cheers,

Charles