Kathy Su’s paper on wingspot evolution in Science

Citation: Arnoult, L., Su, K. F., Manoel, D., Minervino, C., Magriña, J., Gompel, N., & Prud’homme, B. (2013). Emergence and Diversification of Fly Pigmentation Through Evolution of a Gene Regulatory Module. Science, 339 (6126): 1423-1426.


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Kathy Su obtained her Honours and Masters degrees at NUS has successfully completed her Ph.D. in France and is now back in Singapore to pursue her post-doctoral research at the Evolutionary Biology Lab.

Her doctoral research on the evolution of wing spot patterns in Drosophilid flies was recently published in the journal Science.

The study illustrated how the appearance of darkened wing spots within a group of closely related flies was orchestrated by the assembly of a gene regulatory network involving several pigmentation genes under the regulation of at least one shared transcription factor.

This study has broad implications and provides insights into the emergence of novel morphological traits and their subsequent diversification. Her study was also featured recently in the French press, Le Monde.

Congratulations Kathy on your recent publication!

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Tue 16 Apr 2013: 3.00pm – William Eckman on “Ecology and Restocking of Giant Clams”

Qualifying  Examination

“Ecology and Restocking of Giant Clams”

William Eckman
Graduate Student,
Dept. Biological Sciences, NUS

Tue 16 April 2013: 3.00pm
@ DBS Meeting Room
(S3 Level 5,General Office #05-010)

Supervisor: Asst Prof Peter Alan, Todd

All are welcome

Abstract:

“As giant clams inhabit shallow waters, primarily in developing nations, many of their species are in danger of becoming directly extirpated by human activity, or of being unable to reproduce due to falling population densities. Over their long lifespans, giant clams produce large numbers of offspring, which have low survival rates at the larval and juvenile level. This is a successful reproductive strategy in the absence of human intervention.

Archaeologists know that humans have been harvesting clams for thousands of years, but modern technologies such as commercial fishing boats and SCUBA gear are depriving clams of refugia from which to repopulate other reefs. Increasing water turbidity due to coastal development, eutrophication, and dredging can make deeper water uninhabitable to giant clams, forcing their populations to reestablish in areas where they are more vulnerable to harvesting, tropical storms, and increasing water temperatures.

There is a significant amount of scientific literature regarding giant clams, particularly regarding their anatomy, physiology, and their symbiotic relationship with zooxanthellae. However, there are major gaps in the areas of their general ecology, reproductive behavior, and larval stages.

I will present the results of my experiments to determine giant clam larval tolerances to elevated water temperature, reduced light penetration, and reduced salinity.

I will also outline a proposed general ecology paper which will highlight and attempt to quantify the role that giant clams play in maintaining healthy reef ecosystems. There have been attempts in many countries to restock reefs with giant clams, although success rates have been low. Those efforts have not documented their strategy for placing clams in order to achieve high rates of survival and reproductive success.

I have carried out some preliminary investigations into giant clam reproductive behavior, and will continue and expand that work into a model resulting in guidelines for optimal clam placement. Clams in restocking efforts are initially placed in anti-predator cages, but their design is haphazard. I will experimentally compare several designs, including intertidal, benthic, and floating models, to determine which is most suitable for clam protection and growth in Singapore’s waters.

Finally, I plan to investigate the impacts of sediments on giant clams, using machinery which is capable of varying the timing and intensity of sediments to simulate various environmental or anthropogenic events.”

Job: Manager at National Biodiversity Centre, NParks

Careers@Gov

Application details at NParks webpage.

Responsibilities

The Biodiversity Information and Policy branch under the National Biodiversity Centre is responsible for developing biodiversity information products and services, coordinating and promoting collaboration and partnerships in enhancing urban biodiversity and ecology in Singapore, driving the implementation of policies and guidelines pertaining to biodiversity conservation and managing the implementation of the National Biodiversity Strategy and Action Plan.

Key responsibilities

The successful applicant is required to facilitate and steer biodiversity research towards conservation priorities in support of Singapore’s National Biodiversity Strategy and Action Plan, manage the research application and approval process, organize biodiversity research presentations and workshops and to regularly review the kind of biodiversity research being conducted in Singapore.

Requirements

  • Degree from a recognized university and at least 3 years of work experience
  • Have at minimum a first degree in a relevant discipline
  • Keen interest and passion in biodiversity conservation
  • Strong organization and analytical skills
  • Good writing and interpersonal / communication skills
  • Competence in database management and experience in using Global Information Systems (GIS) will be an advantage
  • Some experience in doing scientific research work

Only shortlisted candidates will be notified.

See also other jobs at the NParks webpage.

BBC Nature News features research on ghost crab camouflage conducted in Singapore

Citation: Stevens, M., P. R. Cheo & P. A. Todd, 2013. Colour change and camouflage in the horned ghost crab Ocypode ceratophthalmus. Biological Journal of the Linnean Society. doi: 10.1111/bij.12039


A paper published in the Biological Journal of the Linnean Society about ghost crab camouflage arose from a collaboration between Martin Stevens, Peter Todd and his hons student Cheo Pei Rong. BBC Nature News picked up the story on 5th April 2013:

BBC Nature - Horned ghost crabs change camouflage from day to night

This was picked up by WildSingapore when it first came out .and circulated in the local naturalists community. To find out more about this crab on our shores, Wild Singapore which has a page on Ocypode ceratophthalmus here.

Abstract – Species that change colour present an ideal opportunity to study the control and tuning of camouflage with regards to the background. However, most research on colour-pattern change and camouflage has been undertaken with species that rapidly alter appearance (in seconds), despite the fact that most species change appearance over longer time periods (e.g. minutes, hours, or days).

We investigated whether individuals of the horned ghost crab (Ocypode ceratophthalmus) from Singapore can change colour, when this occurs, and how it influences camouflage.

Individuals showed a clear daily rhythm of colour change, becoming lighter during the day and darker at night, and this significantly improved their camouflage to the sand substrate upon which they live. Individuals did not change colour when put into dark conditions, but they did become brighter when placed on a white versus a black substrate.

Our findings show that ghost crabs have a circadian rhythm of colour change mediating camouflage, which is fine-tuned by adaptation to the background brightness. These types of colour change can enable individuals to achieve effective camouflage under a range of environmental conditions, substrates, and time periods, and may be widespread in other species.

Martin Stevens, Peter Todd and his student Cheo Pei Rong

Wed, 17 Apr 2013,10am @ S1A SR: Mindy Tuan on “Comparative and experimental approaches to understanding sexual selection of sepsid flies”

Qualifying  Examination

“Comparative and experiment approaches to understanding  sexual selection of sepsid flies”

MINDY

Speaker: Mindy Tuan 
Graduate Student,
Dept. of Biological Sciences, NUS
Wednesday, 17th April 2013: 10.00am
At the S1A Seminar Room, S1A- 02-17
(Next to the S1A Car Park/CBIS)
Supervisor: Prof Rudolf Meier

All are welcome

Abstract:

“Males often differ from females by having exaggerated ornaments and/or performing complex behaviours. Such sexually dimorphic traits are usually the product of sexual selection and can be morphological, behavioural, chemical or tactile in nature.

Here I use sepsid flies to study the evolution of such sexual dimorphisms to test whether they evolve faster and make a more significant contribution to speciation when compared with non-sexual traits.

Sepsid flies occur worldwide and comprise over 300 species. They possess a fascinating array of sexually dimorphic morphological and behavioural traits that are used during mating. In my research, I use sepsid flies to quantify the amount of correlated evolution between morphology and behaviour, study the evolution of copulation duration, and compare character change in pairs of closely related species and distantly related, allopatric populations.

My comparative work on 30 species already shows that sepsid fly mating behaviour varies tremendously, with flies assuming static positions and performing dynamic actions that are largely sex-specific. Furthermore, my data clarifies the relationship between morphology and behaviour by indicating instances in which morphological change is linked to behavioural change, and instances in which there is no such correlation.

I also studied the evolution of copulation duration across the 29 taxa and demonstrate that it evolves quickly although there is a significant phylogenetic effect with “basal” species having longer copulation times. I am currently testing whether this pattern correlates with the complexity of behaviour and morphology.

Moreover, I will look for traits that are influential in speciation, by studying morphological, behavioural and chemical traits in groups of closely related sister species (genetic distance for COI: 0-3%), as well as distantly related populations of a species (genetic distance for COI: 1.5% to 3%). Preliminary data suggest that behavior and morphology may evolve the fastest while the chemicals in a sexually dimorphic male gland evolve slowly.”

New paper by Matthew Lim & Li Daiqin – Jumping spider’s UV-green iridescence predicts the physical endurance of males

Citation: Lim MLM & D. Li, 2013. UV-Green iridescence predicts male quality during jumping spider contests. PLoS ONE, 8(4): e59774. doi:10.1371/journal.pone.0059774.


Congratulations to Matthew Lim and Li Daiqin for their recently published PLoS One paper, “UV-Green Iridescence Predicts Male Quality during Jumping Spider Contests” – see PLoS One

PLOS ONE: UV-Green Iridescence Predicts Male Quality during Jumping Spider Contests

“This paper primarily investigates the correlations of a salticid’s structural colours (i.e., UV-green iridescence) with individual quality (i.e. physical endurance during male-male competition), providing insights into the role of ‘pure’ structural colours during animal contests.”

Abstract – “Animal colour signals used in intraspecies communications can generally be attributed to a composite effect of structural and pigmentary colours. Notably, the functional role of iridescent coloration that is ‘purely’ structural (i.e., absence of pigments) is poorly understood.

Recent studies reveal that iridescent colorations can reliably indicate individual quality, but evidence of iridescence as a pure structural coloration indicative of male quality during contests and relating to an individual’s resource-holding potential (RHP) is lacking.

In age- and size-controlled pairwise male-male contests that escalate from visual displays of aggression to more costly physical fights, we demonstrate that the ultraviolet-green iridescence of Cosmophasis umbratica predicts individual persistence and relates to RHP.

Contest initiating males exhibited significantly narrower carapace band separation (i.e., relative spectral positions of UV and green hues) than non-initiators. Asymmetries in carapace and abdomen brightness influenced overall contest duration and escalation.

As losers retreated upon having reached their own persistence limits in contests that escalated to physical fights, losers with narrower carapace band separation were significantly more persistence.

We propose that the carapace UV-green iridescence of C. umbratica predicts individual persistence and is indicative of a male’s RHP.

As the observed UV-green hues of C. umbratica are ‘pure’ optical products of a multilayer reflector system, we suggest that intrasexual variations in the optical properties of the scales’ chitin-air-chitin microstructures are responsible for the observed differences in carapace band separations.

matthew-spider (Cosmophasis umbratica)
Photo of male Cosmophasis umbratica by Matthew Lim

Fri, 19 Apr 2013, 4.00pm @ DBS Conf Rm: Chong Kwek Yan on “The Effects of Urban Greenery on Biodiversity”

PhD Defense Seminar cum Oral Examination

“The Effects of Urban Greenery on Biodiversity”

CKY
Chong Kwek Yan
Graduate Student
Dept. of Biological Sciences, NUS
19 April 2013, Friday
4:00PM
DBS Conference Room (S3, Level 5)
Supervisor: Assoc Prof Hugh Tan T W

All are welcome

Abstract – “The world’s growing urban population and urbanized areas have occurred in areas with high biodiversity value. Frontiers of urbanization are also approaching protected areas and encroaching upon habitats of threatened or endemic species. Urbanization usually involves the destruction of habitat when natural vegetation is cleared to make way for buildings and roads, but cultivated greenery and open green spaces such as parks are also created. Such greenery and green spaces have been used as urban planning tools to improve the quality of life for human residents in cities, but have also been thought to be able to improve habitat quality for urban wildlife.

Using data from surveys of birds and butterflies, and satellite imagery in Singapore, my analyses show that cultivated tree cover and natural vegetation both promoted alpha diversity, while traffic density reduced alpha diversity. However, after controlling for the confounding effects of alpha diversity on community dissimilarity, cultivated vegetation was found to produce homogeneous bird and butterfly communities compared to natural vegetation. In addition, there was evidence of interactions between traffic density and tree cover.

In addition, I explored how abundances of 20 most common bird species in a subset of transects that were surveyed a decade ago (from 2000 to 2001) have changed, and if changes in abundance were related to changes in the urban landscape, or attributable to species interactions. The brood parasitic Asian koel (Eudynamys scolopaceus), which is known to prefer house crow (Corvus splendens) as hosts, has increased in abundance even though the house crow has declined from culling. There was also no evidence that the decline in house crow abundances through culling had resulted in release from competition for its co-invading alien, the Javan myna (Acridotheres javanicus). Instead, increased urbanization was correlated with the increase in abundance of the Javan myna.

In conclusion, cultivated greenery has not been a good substitute for natural greenery in terms of providing for biodiversity. This poses problems for maintaining truly urban biodiversity in compact cities such as Singapore, where future urbanization will necessarily involve the loss of remnant or regenerating natural vegetation within the built-up areas.”

 

Thu 04 Apr 2013: 2.00pm @ DBS Conf Rm: Lynette Loke on “Enhancing biodiversity on tropical seawalls”

Qualifying Examination

“Enhancing biodiversity on tropical seawalls: the role of habitat complexity in regulating the diversity and composition of intertidal communities”

(4) Lynette Loke - NUS BioD CrewLoke Hui Ling, Lynette
Graduate Student,
Dept. of Biological Sciences, NUS
Supervisor: Asst Prof. Peter A. Todd

Thu 04 Apr 2013: 2.00pm
DBS Conference Room (S3, Level 5)

All are welcome

Abstract – “Increasing coastal urbanisation has resulted in widespread replacement of natural habitats with large-scale artificial structures, such as seawalls, which tend to support less diverse biological communities. With the realization that such infrastructure cannot be removed, there is now a call for more research into ways seawalls can be built to increase their value as a habitat while meeting engineering criteria.

To understand how seawalls can be better designed, I first focused on improving their structural complexity. Habitat complexity has been hypothesized to be one of the primary drivers of biodiversity, however, the mechanism(s) by which it does this remains unclear. One of the greatest impediments to advancing this critical area is the ambiguity regarding the definition of ‘complexity’.

In addition to making comparisons of ‘complexity studies’ highly problematic, this lack of terminological clarity and precision has undermined attempts to standardise the measurement of habitat complexity or to develop indices that can be used to create artificial habitats with different levels of complexity—an essential first step for both systematically studying the relationship between habitat complexity and biodiversity and for creating artificial habitats for restoration efforts.

I address these issues by describing a new framework for conceptualising ecological complexity and then introduce a novel software program that enables users to visualize static, physical complexity. My program also provides output files that can be used to create artificial substrates at any scale and level of complexity for experimental and/or restoration and reconciliation studies. With it, I built concrete tiles to test for the effects of complexity and different component types (while controlling for area) and subsequently, the effects of scale and water-retention.

With the knowledge gained from these experimental studies, I plan to design and fabricate a composite tile (BioBoss). Using this new tile, I will investigate the effects of other processes, including hydrodynamics, fragmentation and population dynamics.