Two new preprints!

Last week we managed to get out two new preprints!

Firstly, are parthenogenetic species avoiding the costs of parthenogenesis by having cryptic sex?

In our new paper, we screen for genetic signatures of cryptic sex in eight populations of parthenogenetic Timema stick insects and found evidence for sex in two of them!

Cryptic sex is likely mediated by rare males and may help to explain the unusual success of parthenogenesis in Timema. This also raises the question of whether episodes of rare sex are in fact the simplest explanation for the persistence of many old parthenogens in nature.

This work was led by Susana Freitas with help from myself, Marjorie Labédan, Zoé Dumas, and Tanja Schwander.

In the second paper, we find not only that Diploscapter nematodes differentially infect foraging ants (Ooceraea biroi) but also that they change the behaviour of their hosts so they spend less time outside the nest. This has the effect of reducing the division of labour and increasing the spatial overlap between hosts, which is expected to facilitate parasite transmission.

This means that division of labour not only shapes infection risk and distribution but can also be modified by parasites.

This work was led by Zimai Li in Yuko Ulrich’s lab.

New module!

Excited to announce our new third-year module ‘Animal reproductive strategies’ has just been accepted for inclusion into the new (2025) curriculum for Zoology!

Jointly organised with Kirsty MacLeod, in this module we will examine the causes and consequences of the incredible diversity of reproductive strategies found in animals.

Photo credit: Chun-Che Chang

Merry Christmas!

….And just like that my first semester as a lecturer draws to a close. It has been a crazy few months but overall was a lot of fun!

A few things I have learned:

Writing lectures takes a long time.
Practical session prep takes even longer.
Teaching would collapse if it wasn’t for the technicians.

Enjoy your break everyone!

Christmassy Main Arts
Snowy hills
The lecture theatre
Some pinned specimens
Some live specimens

Welcome to the new students!

Great to welcome our new (and largest ever) cohort of students last week with a trip to Treborth Botanic Gardens!

Now I’d better actually write some lectures…

New paper published!

How do genes on sex chromosomes evolve in Timema?

In our new paper, we identify and examine patterns of sequence evolution and gene expression on the X chromosome across five Timema species.

Overall we find consistent evidence for relaxed selection on the X and complete dosage compensation in somatic tissues but not the reproductive tracts.

Interestingly, we also find that genetic diversity is much lower on the X than expected (X to autosomes ratio of 0.19 to 0.48, much lower than the expectation of 0.75), which may be due to a combination of a lower effective recombination rate on the X and population bottlenecks.

Finally, we find that dosage compensation in Timema seems to be due to the upregulation of the X chromosome in males. This mechanism is also common to all other XX/XY or XX/X0 insect systems yet studied, suggesting that this mechanism may be universal for insect species with heterogametic males.

MEEB biannual meeting

MEEB-ers assemble!

Yesterday we held the MEEB biannual meeting to discuss updates and problems, and to assign roles to group members.

Surprisingly fun and great to meet with (almost) all the MEEB members in person!

New paper published!

Does developmental strategy influence the development of sex-biased gene expression?

In our new paper, (led by PhD student Jelisaveta Djordjevic) we take a first look at this question in insects by examining sex-biased gene expression across development in a hemimetabolous insect (Timema californicum). We find that sex-biased gene expression develops more gradually and to a lesser extent than in holometabolous insects.

This suggests that hemimetabolous development may constrain the evolution of sex-biased gene expression, but we need more developmental gene expression studies in hemimetabolous insects to verify this!