New research life in Edinburgh: fieldwork in California, blogging about nature crazy sex life and more

2017-04-11 11.54.31
Vine mealybugs in North California vineyard

Hello everyone,

A lot has happened since I moved to Edinburgh. Here are the main updates:

  • I am currently carrying out fieldwork in California until May, and looking for obscure mealybugs with B chromosomes. Follow me on Twitter!
  • In August, you will see me at ESEB2017 in Groningen, where I will present my work on scale insect adult metamorphosis.
Advertisements

Why should biologists use GitHub?

Screen Shot 2016-05-08 at 3.45.28 PM
from GitHub repository here

Today, all biologists use computers on a daily basis, produce and analyse data. A lot of us now have to learn programming (even just some bits of it).

I am not a computer scientist/engineer, and I am far from a bioinformatics person (yet), but I have started to discipline myself to make my published research as reproducible as possible and this is not only by depositing DNA sequence data to NCBI, but also analysis pipelines and command lines made available to the public on GitHub.

GitHub is a great public repository hosting service for publishing programming source code, but it can also be used to detail your analysis pipeline and code, and even create tutorials on softwares or pipelines for others.

For example, the Trinity tutorial from Brian Haas was a life saver for a biologist like me that had never touched any next-generation sequencing data.

As a biologist, to support my recent publication on scale insect phylogenetics, I created a GitHub repository that details all the steps and command lines in MrBayes and R analyses. This provides transparency to the reader and more rapid reproducibility.

Tip: If you are worried about your analysis pipeline or data being online during the manuscript review process, academic researchers can apply for free space for 5 private repositories. For more information, check here.

Nowadays, a lot of biologists will come to work in a multidisciplinary environment, and it implies learning new skills. In bioinformatics in particular, workshops are available but the internet is a great resource to learn skills by ourselves and GitHub can help both learning how a software works, but also making the details of informatics methods available to other biologists that are also learning how to use these softwares (from command lines for de novo assembly using Trinity or making a simple plot with R).

 

 

Extreme sexual dimorphism in scale insects: why do males and females look so different?

The amateur of gardening would have encountered those annoying and strange looking insects, covered with white cotton or a very hard small scale. Scale insects suck the sap of your favorite rose plant or cherry tree. But, blame it on the females! The insect you will encounter on the stems or leaves are always adult females or juveniles. The adult male is not only not easily spottable but when so, they just look so different that you might think it is a fly.

Scale insects are extremely sexually dimorphic. This dimorphism has been present for as long as scale insects originated, for the fossil record have not uncovered yet any female that look like males. To give you an idea of the dramatic dissimilarity, here are some treasures that I found from Flickr.

Ortheziidae (ensign scale insect) -> here

Pseudococcidae (mealybug) -> here (the male is on top of the female, while an ant is looking for honeydew on the female’s butt)

Coccidae (soft scale insect) -> here (the male is sitting on top of the brown flat female)

NB: Sorry for sending you to the Flickr website, I don’t want to misuse the copyright of these photos.

How does it happen?

Notebook 4-7

After hatching, males and females look just like one another. During the first instar nymph, even microscopic differences cannot be observed. However, at some point during the second instar nymph, males and females reveal their true selves. From then on, they undergo completely different developmental pathways.

  • The juvenile female carries on to successive molts, basically becoming bigger and bigger but not changing at all in appearance. By the last molt, the female is considered adult because of her reproductive organs, but will just look like a juvenile. Females are neotenic.
  • The juvenile male starts secreting white cottony filaments that will be used as protection and hide him away during his dramatic metamorphosis. Males go through non feeding stages where wings develop progressively. When the adult male emerges, he looks completely different from the juvenile, with wings and elongate body and long antennae and legs, but lacks mouthparts.

Scale insects belong to the order Hemiptera, which are hemimetabolous insects (developing through successive molts and progressive wing development). However, in the case of scale insects, both males and females act differently from their “normally” developing cousins: females don’t develop wings (never ever) and are virtually juveniles with reproductive organs, and males go through a development stage that looks like a fly metamorphosis (but not quite the same).

In short: scale insects are unconventional and developmental rebels.

My postdoctoral work is looking at the hormonal regulation point of view to understand how males and females, looking so similar in the beginning, followed different paths and ended up looking like different  insects.

Stay tuned for some outcome of my research!