BioPS 2017

The BioSciences Postgraduate Society recently held their AGM (how time flies) and have elected members of the next committee. It has been a pleasure to serve as Vice President on the committee. Last year we heard from industry, academics, post-docs and fellow students on a range of topics about careers and research. We had parties of various themes, and even a baking competition. And finally, we set up a volunteer mentoring program for grad students, connecting them with fellow students or post docs. Thank you to all the members of the previous committee for their hard work and dedication, and to all the other postgrads for participating in events.

And so, I have been elected as President of BioPS for the next year. I look forward to continue to serve and organise events for the postgrads of BioSciences.


Native Biodiversity Photo Competition

A well-known fact among scientists is that science and beer mix very well. The Pint of Science festival just finished this week. This is a global event where scientists give brief talks about their work at a pub. I went to an event in Melbourne and one of the speakers, Euan Ritchite from Deakin University, raised a very good point about Australian marsupials:

Many Australians cannot identify a native marsupial that is not a prolific species such as the koala, kangaroo, wombat or platypus.

It makes me feel a little better about my own knowledge of Australian natural history. As an expatriate Australian I have always felt a bit behind in my knowledge of Australian biota compared to peers who have lived here their whole life. But what it does exemplify is an emerging realisation that we, as a society, may be at risk of a disconnect between our lives and the surrounding natural world. This has consequently generated an interdisciplinary field to examine the relationship between society and nature in and around cities, that merges social science, urban ecology, urban planning, conservation biology, and even human health and well-being. But that is another story.

One way we can overcome this disconnect and get people to care about nature is to encourage engagement with nature. And that is what the Graduate Student Association at the University of Melbourne have done. They have organised a photo competition for native biodiversity on any university campus, the Sustainability Prize. The subject of the photo has to be a native Australian species, flora or fauna, and had to be taken with a smart phone camera.

I think this was a great idea and it definitely made you look at the species you see every day and think ‘is this a native species?’. It was even a good reason (excuse) to go for a walk to try to snap a good photo. Anyway, I decided to enter a photo I took during Spring of hover flies enjoying a flower outside Biosciences 2. Here is the photo:

#hoverfly #flower #garden #spring

A post shared by Jacinta Kong (@jacintakong) on

And it won a runners-up place! Which is nice 🙂 Here is me enjoying my win:

You can find the complete list of winners here.

I hope little initiatives like this encourage people to think about the natural world and the impact they have on it. After all this is the Anthropocene.

Water vapour and insect egg development

Water is an important factor in the ecology of many insects (see Hadley (1994) for a general review of across all arthropods). However, water is often overlooked in experimental studies in favour of other environmental variables, particularly temperature and photoperiod. The source of this bias is probably two-fold, firstly temperature and photoperiod are easier to manipulate in a laboratory setting than water. Secondly, when researchers talk about water and insects they usually mean liquid water but for insects, the sources, significance, and function of liquid water depend on the context. This also results in a complicated (but what isn’t?) relationship and compounds to the first challenge.

I work on insect egg development so let us explore the second challenge using insect egg development as examples. For insect eggs buried in the soil, the main determinant of water availability is the water potential of the substrate. Water potential is the capacity of a substrate to hold water, or in other words its affinity to water. Particle type, particle size, mineral content, and bulk density (the amount of air space) are some of the many variables that determine the water potential of a substrate. Contrast this to eggs laid above ground where water potential is not important. For example, an egg on a leaf could receive water from precipitation that is trapped around the egg or the leaf, perhaps due to the surface tension of water. For either case, metabolism is another potential source of water, but this requires development to have started. An egg currently in desiccation-induced dormancy may not be metabolically active for effective production of metabolic water. I won’t go into the importance of water for insect dormancy responses here – but it is important.

But what about water vapour?

Eggs above ground are surrounded by water vapour. Water vapour could come from the air or transpiration from the leaf, to stick with the leaf example. Water vapour is not liquid water but has been shown to be effective in insect development. Yoder and Denlinger (1992) is the first paper describing the role of water vapour for egg development of a stick insect, Extatosoma tiaratum. In the paper, they also found no evidence for water vapour uptake in other insect species examined. There hasn’t been a more recent examination of this relationship in insects since this paper (or have there? I’d like to know), but see Yoder et al. (2004) for an example in ticks. Moreover, where liquid water is involved it is almost impossible to isolate the presence of water vapour, especially within a small enclosed space so it is not inconceivable for eggs to uptake water vapour even in the presence of liquid water.


Early in my PhD I received a stick insect from my supervisor (who only ever seems to give me insects as presents [1]). This stick insect, a Sipyloidea nelida I think (left picture), eventually matured and parthenogenetically produced some eggs (unless a male stick insect snuck into the cage for a rendezvous but highly unlikely). I said I was going to try to hatch the eggs but I never did, for two years. During that time those eggs have been sitting in the laboratory, either at 25 or 30°C and about 30% RH, out of sight out of mind. When I did have a look several months later, one of the eggs had hatched, and I’m certain I have not intentionally sprayed them. I’ll save you from some grizzly photos of mummified nymphs.

I opportunistically collected more Sipyloidea eggs from Western Australia and kept them together. I think I sprayed these eggs only once after I found the first hatched egg and kept the PCR tubes I stored them open, but I can’t remember exactly when that was so I never directly took them out and sprayed them. A year after collecting them and months after getting sprayed, I checked the eggs again while cleaning the lab and found 5 more nymphs had hatched. Did they hatch after one indirect spray of water? Or did they receive enough water from the water vapour in the air? I have incubated the remaining eggs under various water conditions but in any case, I can’t answer those questions, unfortunately. I had eggs from only three females, each from a different location and from two species.

It would be awesome if this genus of stick insect was able to meet its water requirements for egg development from water vapour alone. It’s probable that the ability to uptake water vapour is a more widespread trait than currently known since it has only been looked at in a few distantly related taxa. This trait would also be ecologically interesting for this parthenogenetic genus because this genus is widely distributed across Australia, including arid and semi-arid zones. Independence from the presence of liquid water would be a neat adaptation to the dry and unpredictable climate of the Australian bush, which would potentially explain their widespread distribution. These eggs have a morphological feature at the anterior end of the egg which looks like part of a dandelion fluff. The role of this morphological feature is to collect water, presumably liquid water but an alternative explanation is that it allows for the condensation and collection of water vapour. Perhaps a project for another student at another time?

For experiments, manipulating water potential in the laboratory is not impossible. Vermiculite is one option, I’ve never used it so I can’t say how accurate it is. Extremes of the wet/dry spectrum are easy enough. Desiccants such as Drierite will remove water vapour for as long as it is active. Water vapour is commonly measured by the relative humidity, but can also be quantified as the dew point. Relative humidity is the amount of water vapour in the air compared to the total amount possible at a given temperature. Dew point is the temperature at which water droplets will form. Most papers will refer to relative humidity (if at all) but it may not be as descriptive as dew point. Like water potential, water vapour is not easy to manipulate in the lab and has the extra complication of requiring chemicals (there may be other ways of doing this). Super-saturated aqueous solution of different salts will produce different relative humidity. Conveniently, salt (NaCl) will produce a relative humidity of 75%, there are tables of this information, try Wexler and Hasegawa (1954).

Although water is experimentally more challenging to manipulate and control in a laboratory setting than commonly measured variables, and influences individuals in many ways and forms, water in any phase should not be overlooked in studies because the presence of water can also be dependent on other variables or vice versa. A humid day may feel hotter than a dry day of the same air temperature because of the lack of evaporation. After all, water is only one of the many interlinked environmental variables that, in combination, affect the ecology, behaviour, and physiology of individuals.

UPDATE: none of the eggs have hatched at 30°C regardless of water availability. The eggs looks like they have started developing but maybe something is not quite right for them to hatch.


Hadley, N. F. 1994. Water relations of terrestrial arthropods. Academic Press, Inc., San Diego.

Wexler, A., and S. Hasegawa. 1954. Relative humidity-temperature relationships of some saturated salt solutions in the temperature range 0° to 50°C. Journal of Research of the National Bureau of Standards 53:19-26.

Yoder, J. A., J. B. Benoit, and A. M. Opaluch. 2004. Water relations in eggs of the lone star tick, Amblyomma americanum, with experimental work on the capacity for water vapor absorption. Experimental and Applied Acarology 33:235-242.

Yoder, J. A., and D. L. Denlinger. 1992. Water vapour uptake by diapausing eggs of a tropical walking stick. Physiological Entomology 17:97-103.

[1] Number of insects I have received from him, excluding ones collected on joint field trips = 29 and expecting more at the time of writing– FYI cake is also acceptable [2].

[2] Number of baked goods I have received, excluding at parties = 0

It’s that time of the year again!

It’s summer in the Southern Hemisphere! Which means the scientific community is waking from their winter slumber to enjoy the sun and scientific gatherings.

Between the 27th November and 7th December there were four meetings of relevance to me that were scheduled one after another: the Ecological Society of Australia, the joint meeting between the Australian Entomology Society and New Zealand Entomology Society, the Australian and New Zealand Society for Comparative Physiology and Entomology, and the School of BioSciences Postgraduate Symposium. I chose to go to AES/NZES instead of ESA because they directly clashed.

I accidentally missed the abstract deadline for AES/NZES so I didn’t present at the conference, but it was in Melbourne so I went anyway and it was a great opportunity to network and see what other people work on. It was my first time at AES and so far has been the largest and most diverse conference I have been to. The student trivia night was load of fun and had great table decorations, as you can see below.

A photo posted by Jacinta Kong (@jacintakong) on Nov 29, 2016 at 4:01am PST


Then it was off to Western Sydney University for ANZSCPB (fondly nicknamed the alphabet conference by attendees). This my second year at ANZSCPB and it was a larger meeting than last year and even more rewarding in that respect. I gave a short (3 mins) update of my research this year and I had a great time seeing old acquaintances and meeting new ones. It was great to see more student research, especially from Honours students. I also managed to visit a lab or two at the University of Sydney and the Australian Museum in downtown Sydney, where I found a thylacine!

A photo posted by Jacinta Kong (@jacintakong) on Dec 5, 2016 at 3:58am PST


Finally, it was the second annual postgraduate symposium back at the University of Melbourne. Partly student organised and run, it was a great showcase of all the postgrad research happening in the school. Well done to everyone involved! I was particularly impressed by the turnout from MSc students from all research areas of the school, since it was not compulsory for them, unlike us second year PhD students. I didn’t get to go last year because I was at ANZSCPB but from what I’ve heard it was an improvement from last year. The School as an organisational unit is still relatively new and I hope the research culture continues to develop with the enthusiasm of the younger generation of postgrads.

Next year I hope to attend a meeting overseas 🙂

Reproducibility, R and data

The word of the day is Reproducibility. For as long as I have been using R I have been manually copying and pasting R codes, output and graphs into word documents. Too long, too troublesome. That’s when I discovered RMarkdown, an implementation of Markdown in R, which allows you to create documents with formatting similar to that seen in LaTeX and embedded R code and output all in one handy place. Needless to say I have been extremely distracted and excited about analysing my data with this new workflow. R scripts aren’t good enough on their own anymore but full LaTeX does not suit my needs.

The most recent update of RStudio includes a slight extension of this: RNotebook which will allow you to preview the final document without having to generate the complete document every time (which can take a while). I am excited by this update, for example it will run multi-line code automatically, but so far I have found the update to be a bit laggy and cumbersome. The console stubbornly refuses to switch to another pane and the automatic display of output within the script can make the screen messy.

At the same time I have been using the opportunity to get into the habit of not relying on base functions, especially for plotting. I have been playing with ggplot2 and the colour palette package viridis, which I highly recommend.

I have spent most of the year, indeed most of my PhD, collecting data. Another useful tool we have established is a MySQL database implemented in R through RMySQL. It’s a steep learning curve if you are not familiar with relational databases and SQL syntax but it is great when you have lots of independently collected data that you want to collate and analyse together in various ways.

Conference season is coming up so it is time to sit down and look at all this data I have been collecting and neglecting to analyse through the year. I am looking forward to attend the Australian Entomology Society Conference in Melbourne, and I will be presenting at the Australian and New Zealand Society for Compararive Physiology and Biochemistry held at Western Sydney University.

Bake Your PhD

This month the BioSciences Postgrad Society hosted a Bake Your PhD competition for a bit of fun. We had many amazing entries that were judged by the Head of School, Mark Burgman, as our guest judge. Congratulations to all the winners and thanks to all who participated or came to eat some cakes.
Here is mine, which came third:

A photo posted by Jacinta Kong (@jacintakong) on Aug 5, 2016 at 2:46am PDT


I decorated two cupcakes with two pokémon: a psyduck and a slowpoke because both represent the confusion and dopiness of being a postgraduate student (Mark said the feeling never goes away…).