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Changed seasonality and increasing temperatures are hallmarks of the ongoing climate change and challenge the viability of individuals, populations, species, and ecosystems. Recent research suggests that aquatic ectotherms such as fish, especially early life-stages are vulnerable to increasing temperatures. To understand, predict, and possibly mitigate the consequences of climate change, it is thus crucial to investigate the causes of variation in early life-stage thermal performance of ectotherms. Egg size has received considerable attention in this context, but previous studies have been limited to species and population comparisons, neglecting the role of egg size variation structuring variation in thermal performance among individuals within populations. This constrains our mechanistic understanding of egg size as a modulator of thermal performance and how organisms may respond to climate change. To test how intraspecific variation in egg size influences thermal performance, we conducted a split-brood experiment where eggs from 64 female pike (Esox lucius) from the same population were fertilized and incubated at four temperatures until hatching. Results showed that larger eggs had higher hatching performance in low temperatures whereas smaller eggs were more successful in higher temperatures. This suggests that fitness advantages associated with larger eggs may change in the future climate.

SEB Conference 2024

Smaller pike eggs outperform bigger eggs in a global warming scenario

Welcome Seabirders!  

Welcome to Virtual World Seabird Conference 3 - vWSC3! Whether you are in your office or lab, at home, in a coffee shop or bar poaching some wifi, or at a remote field site or research vessel – we are very excited to welcome you to the third ever World Seabird Conference. 

We would like to thank ALL of you for being so patient as WSC3 was scheduled, postponed, rescheduled, revised to virtual, and scheduled again. Throughout all those iterations there was one message that remained perfectly clear – seabirders were eager to meet and share their science. If we could not meet in person then virtual it would have to be, but a 3rd WSC was something everyone wanted. That support and commitment helped the WSU Board of Directors and Member Societies sort through all of the challenges they faced to plan and hold this conference. 

The list of those that need to be thanked is long and, while we plan on recognizing many during the live closing plenary, it is important to do so here in writing as well. 

The Australasian Seabird Group was our Local Host for our plan to meet in Hobart, Tasmania. They invested substantial time and effort to find venues and plan events that we unfortunately were not able to visit. Nonetheless we appreciate their work on behalf of WSC3 and encourage all of you to thank them when you see their members in Gathertown or elsewhere during our virtual meeting. Their willingness to host created the initial excitement for WSC3 and without that our vWSC would not have been possible.

We also wish to thank the Science Program Committee, the Virtual Committee, and the Early Career Scientist Committee for their hard work planning the logistics, events, and schedule for vWSC3. These committees also had to deal with changing parameters and short timelines that made what is always a challenging task even more challenging. The Travel Awards Committee also invested time and effort in developing procedures for awarding travel funds that ultimately would not be implemented. 

Our ability to shift from an in-person to a virtual meeting, and to do so in a way that would be financially feasible, was due to the effective efforts of The International Fundraising Committee and to our financial sponsors. The IFC raised funds to support WSC3 and then, through the good relationships they built with sponsors, ensured we could re-envision how those funds could be used to support a virtual conference that would be affordable and high-quality.

We all owe the WSU Board of Directors and the Representatives of the Member Societies a great deal of thanks. They are the ones who manage the WSU and, for the past 18 months, have had to have a series of challenging meetings and conversations, have had to make a series of difficult choices, have had to do all of that while considering the short- and long-term health of WSU and the World Seabird Conferences, and did this while also managing their own challenges at their day jobs. We are grateful for their diligence, patience, foresight, and throughout all of the meetings, their collegiality. Also – a 6-year term is quite a commitment!

There would not be a WSC3 without a successful WSC1 and WSC2. Thanks go to the Pacific Seabird Group for their support of WSC1 in Victoria, Canada, and to the African Seabird Group for their support of WSC2 in Cape Town, South Africa. In each of these endeavors and for our current conference we were fortunate to work with a dependable and trustworthy partner in Podium Conferences. Michelle Smith and Marischal de Armond have become valued members of our team and have not only helped us plan conferences but have assisted and advised the WSU Chairs and Board on issues above and beyond conference planning. 

As we embark on our vWSC3 week we extend to all of you our thanks for showing up, for being patient, and most importantly for the work you do with seabirds. We are all part of a unique, global community that shares an interest, a fascination, and a passion for birds that make a living in our world’s oceans. We have advanced the science, conservation, and management of seabirds as well the ecosystems they inhabit. We are consistently impressed and motivated by the work you do. 

The WSU formed in 2010 because we saw the need for a global organization to address challenges at a global level. Over the past 11 years WSU has grown, adapted, and evolved to become the community that this week is making vWSC3 a reality. Enjoy the week, appreciate and support the friends and colleagues you have made in the community, and if you see us in a virtual hallway please stop and say hello! 

Thank you for the opportunity to serve all of you and the WSU over the past few years,

Nicholas Carlile, Interim Chair, WSU<br>
Patrick Jodice, 2nd Chair of the WSU<br><br>

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3rd World Seabird Conference

Join us for four days of science, networking and virtual engagement with delegates from around the world!

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SEB’s Annual Conference is celebrated for creating the perfect composition of research, new discoveries and collaborative connections. Be creative and innovative by exchanging ideas and knowledge with masters of biology from all over the world.

Wild organisms are usually infected with a whole range of parasites, however, the infection status of organisms is not usually taken into consideration in ecological and food web studies. The impact that parasites can have on their host organisms, affecting their food intake and internal resource use, might drive to differences in the isotopic composition or niche between infected and uninfected organisms, and thus to erroneous conclusions in stable isotope ecology studies. 
This is the first time that controlled diet-switch experiments and stable isotope analyses (whole tissue, bulk SIA, 13C and 15N) have been performed on a host-parasite system comparing infected and uninfected individuals. Our results highlight the importance of accounting for infection status when conducting ecological studies based on stable isotopes, also contributing to fill the gap of parasite contribution to food webs. 


Importance of accounting for the infection status of an organism in isotope ecology studies: Using feeding experiments as an example

Exploration provides information of the environment and its associated points of interest such as food, threats or mates. However, in experimental biology, exploration is vastly described as distance or area covered by the animals (typically rodents). Usually, experimental tests commonly used in laboratories tend to prioritise the minimisation of variables over the complexity of natural environments. While these setups have provided valuable insights, the technological advent of new analysis and 3D printing technologies, allows us to go beyond overly simplistic environments, in order to better understand animal behaviour in contexts that more closely mimic their natural habitats.
We designed an Enriched Open Field (EOF) by including modular plastic structures in a classic squared open field (OF) arena for mice in order to increase the number of environmentally relevant landmarks in the arena, so as the quantity of regions with exploratory salience. We tested CD-1 and C57/BL6 female mice roaming freely in the EOF and OF arenas for 10 minutes. 
As expected, we observed differences between strains, with greater exploration measures in the CD-1 strain. Animals tested in the EOF showed more consistent exploratory patterns, even if they were previously habituated to the modular pieces in the context of a home cage. The average speed of EOF tested animals was greater and the movement more continuous.
Our study suggests that the presence of structures may mimic more naturalistic environments, thereby promoting exploratory behaviours that are closer to those exhibited in the animals' natural habitat when foraging or looking for social cues. 


Towards a more naturalistic perspective: Enriched open field as an ethologically-relevant exploratory paradigm

The depletion of dissolved oxygen (DO) in global oceans is a growing concern. This phenomenon is observed in coastal and oceanic waters, where different mechanisms contribute. In the Estuary and Gulf of Saint Lawrence (SL), this process of deoxygenation has been documented and is mainly attributed to a greater inflow of the warm, DO-poor North American Central Waters deeper in the water column, isolated by a persistent pycnocline. The responses of organisms chronically under these conditions, particularly benthic invertebrates with low to no mobility, usually encompass molecular modifications (thus complex physiological changes), to cope with environmental hypoxia. Such changes might also be reflected on the proteome, given the range of functions of these molecules on cell structure and metabolism. However, the characterisation of complex proteomic responses in situ is not yet fully addressed. Therefore, the aim of this work is to describe and compare the proteomic profile of a benthic invertebrate across the natural deoxygenation gradient of the SL. We sampled individuals of the annelid Neloeanira tetragona from four subregions across the gradient of the SL and on a well oxygenated outgroup region, the Saguenay Fjord. Proteins were identified and quantified by high resolution LC-MS/MS on whole body samples. The profiles obtained were tested both via pairwise comparisons and multivariate modelling using environmental data. These analyses ultimately highlighted site-specific responses, particularly linked to DO levels, with an overrepresentation of energy metabolism, cell signalling and protein homeostasis pathways. N. tetragona exhibits a compensatory accumulation strategy to cope with environmental chronic hypoxia.

Proteomic profiling across the St. Lawrence River hypoxia gradient: a tale of the worm Neoleanira tetragona

Hearing has evolved independently many times in the animal kingdomand is prominent in various insects and
vertebrates for conspecific communication and predator detection. Among insects, katydid (Orthoptera: Tettigoniidae)
ears are unique, as they have evolved outer,middle, and inner ear components, analogous in their
biophysical principles to the mammalian ear. The katydid ear consists of two paired tympana located in each
foreleg. These tympana receive sound externally on the tympanum surface (usually via pinnae) or internally
via an ear canal (EC). The EC functions to capture conspecific calls and low frequencies, while the pinnae
passively amplify higher-frequency ultrasounds including bat echolocation. Together, these outer ear components
provide enhanced hearing sensitivity across a dynamic range of over 100 kHz. However, despite a
growing understanding of the biophysics and function of the katydid ear, its precise emergence and evolutionary
history remains elusive. Here, using microcomputed tomography (mCT) scanning, we recovered geometries
of the outer ear components and wings of an exceptionally well-preserved katydid fossilized in
Baltic amber (44 million years old). Using numerical and theoretical modeling of the wings, we show
that this species was communicating at a peak frequency of 31.62 (± 2.27) kHz, and we demonstrate that
the ear was biophysically tuned to this signal and to providing hearing at higher-frequency ultrasounds
(>80 kHz), likely for enhanced predator detection. The results indicate that the evolution of the unique ear
of the katydid, with its broadband ultrasonic sensitivity and analogous biophysical properties to the ears
of mammals, emerged in the Eocene.

Auditory tuning to conspecific acoustic signals in an Eocene katydid

Jumping is one of the most commonly used forms of locomotion by insects, and a characteristic trait of the Orthoptera (locusts, crickets, and allies). Their specialised jumping behaviours have evolved for many functions, including traversing long distances, evading predators, and initiation of flight. Although lots of work has been conducted on jumping behaviour across these contexts, jumps which rely on target perception, such as those used for navigating complex environments and hunting prey, have received little attention. In this study, we document a sophisticated vertical jumping behaviour in a neotropical predatory bush-cricket (Tettigoniidae: Meconematinae), whereby visual cues are utilised to aid in perception of target distance. We found that across different target heights (50, 75, and 100 mm), the insect adjusted the properties of its jump to ensure landing. As jump height increased, there was a significant increase in linear velocity (m/s) and decrease in angular velocity (rad/s). This decoupling between linear and angular velocity suggests that the animal is able to perceive the difference in height and establish the jump path prior to take-off. Despite jumping faster to the higher targets, the speed of rotation is adjusted during the jump, allowing the animal to land parallel to the target surface. This study offers evidence that some orthopterans can independently control both the speed at which they take off, and their rate of rotation, based on the visual cue of target distance to achieve a precise and controlled landing.

Jumping up a level: Target distance and angle estimation facilitates successful landing in a jumping glass katydid

Silk Production is one of the most prominent characteristics of spiders. The silk is extruded through spigots located on the spinnerets, which are single- to multimembered paired appendages at the end of the abdomen. Most extant spiders have three pairs of spinnerets, and in between either a cribellum (spinning plate) or a colulus (defunct vestigial organ), dividing these spiders into cribellate and ecribellate species. Previous research has shown that cribellate and ecribellate spiders differ not only in the composition of their spinning apparatus but also in the kinematics of spinneret movements during silk spinning. The objective of this study was to determine whether the differences in spinneret movements are solely due to variations in the degrees of freedom of the spinnerets or whether they are based on differences in muscular anatomy. This was accomplished by analyzing micro-computed tomography scans of the posterior abdomen of each three cribellate and ecribellate species. It was found that the number of muscles did not differ between cribellate and ecribellate species, but there were distinct differences between the species within each group. Muscle thickness, particularly of the posterior median spinneret, varied slightly between groups, with cribellate spiders exhibiting more robust muscles, possibly to aid in the combing process during cribellar thread production. Interestingly, the vestigial colulus still possessed muscles, that could be homologized with those of the cribellum. This initial exploration into spinneret anatomy using micro-CT data reveals that despite being small appendages, the spider spinnerets are equipped with a complex musculature that enables them to perform fine-scaled maneuvers to construct different fibre-based materials.


Comparative anatomy of the spinneret musculature in cribellate and ecribellate spiders (Aranea)

Boobies have the habit of plunging into the sea at high speeds over 90 km/h to capture fish. Their head shape has changed over the history of evolution and this change may have benefitted boobies by the mitigation of impact on the plunge into the water. In this study, we focused on this possibility and investigated a head shape suitable for water plunging from the viewpoint of shock mitigation as well as the evolutional meanings of head shape change. In this research, booby’s head were modeled on the computer based on the CT scanned data of the scull of current and ancestral boobies and the models were printed by 3D printer to be used for the water plunging experiments. The fossil head of the ancestor was deformed during the fossilization process, so it was restored using modeling software. The completed model was plunged into the water surface at a speed of approximately 5.8 m/s, and the impact force was compared by measuring the acceleration at the time of water surface plunge. As a result, it was confirmed that the model based on the head of the present species had a smaller shock per unit volume and had an impact mitigation effect.

Relationship between Head Shape and Impact Mitigation in Plunge Diving Behavior of Boobies

Different bird species exhibit substantial variation in flight behaviour. Flight behaviours are often associated with specific ecological niches and the unique demands that a given habitat or lifestyle imparts. One of the main ways in which niches differ is in how often a bird must use non-steady flight behaviours, such as take-off, landing, or manoeuvring. Due to the link between locomotion and morphology it follows that wing morphology should vary with the relative use of non-steady flight. We here investigated the wing morphology properties that underlay variation in flight behaviour by looking at how external and internal wing morphology relates to ecological parameters that vary in non-steady flight use. We focused on the radius and ulna for our analyses because many of the muscles that are essential for non-steady flight originate or insert on these bones. We hypothesized that the morphology of the radius and ulna varies among bird species in a pattern consistent with how often the species use non-steady flight as predicted by their ecology. We quantified variation in ulna and radius morphology using 3-dimensional geometric morphometrics and used phylogenetic comparative methods to uncover relationships among skeletal morphology, wing shape, and a suite of ecological variables that are linked to non-steady flight use. Our findings suggest that overall curvature and stoutness are major axes of variation for both radius and ulna shape. Furthermore, this morphological variation is potentially related to ecology and non-steady flight use.

Morphological variation of the radius and ulna among raptor (Accipitriformes) species in relation to ecology and unsteady flight behaviours

Fruit flies have been served as a great animal because of its rich genetics. In this research, we monitor weight changes and real-time activities of a fruit fly simultaneously using a force plate. The force plate has a large plate with a diameter of 35 mm which is over 11 times longer than its body length, and a spring structure consisting of four spirals. The force plate uses a glass wafer for preventing strain due to the passage of time, and four spiral cuts are simply fabricated by UV laser marker. The vertical displacement of the center plate is measured by a laser displacement meter fixed under the force plate and converted into the force. The resolution of the force plate is 0.1 µN, which is equivalent to 1/100 of the fruit fly’s weight. In the experiment, a fruit fly is placed in the center of the force plate, and a chamber is covered on top of it. The chamber prevents the force plate from vibrating due to airflow, making it possible to observe changes in fruit fly activity with high precision. Then, measurement is carried out until it stops moving. As it moves on the force plate multiple times, it can be observed that its weight gradually decreases over time. We have confirmed that its weight decreased by approximately 2.3% per hour. It is expected to lead to quantitative evaluation of water evaporation and metabolism from measuring its weight loss.

Long-term weight change measurement of fruit flies using a high-precision force plate

Spiders spin silk into different products, such as fibres, threads and sheets, tailored for specific
functionalities and to fulfil a variety of ecological roles. Examples include draglines and bridging
lines for structural support, as well as webs and sticky threads for prey capture. Most silk products
are made of a combination of different silk fibres with contrasting material properties. The most
common silk types are minor ampullate, major ampullate and aciniform gland silk. Spider silks
exhibit characteristic mechanical properties, including extensibility and tensile strength. How these
properties vary between spider species, gland origins and thread structures as poorly understood.
This study aimed to compare the mechanical properties of different silk products in Pholcidae, with
a particular focus on the cosmopolitan cellar spider (Pholcus phalangioides). P. phalangioides
constructs irregular three-dimensional webs comprising of unique mechanically interesting silk
products. This include capture threads called ‘gumfoots’ which are vertical sticky prey traps
designed to undergo spontaneous deformation and utilizes ‘draglines’ and airborne ‘bridging lines’
which serves for in locomotion and display distinct tensile strength and toughness to hold spider’s
weight. Each of these silk structures were hypothesized to show specific mechanical adaptations.
Preliminary results of tensile test show a significant variety in mechanical properties across
different silk types with varying extensibility, tensile strength and toughness. Further study will
focus on interspecific variation of the structural and mechanical properties of silk products
between pholcid species with different ecology and silk compositions and the composition of fibres
in Pholcidae.

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Importance of accounting for the infection status of an organism in isotope ecology studies: Using feeding experiments as an example

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