Alex Slavenko
@alexsla.bsky.social
Zoologist & ecologist
Obsessed with herps, birds, and PNG
Doing ecological modelling for a living and still shocked by that
Obsessed with herps, birds, and PNG
Doing ecological modelling for a living and still shocked by that
This means the species they studied had ample time to evolve to live in the presence of foxes. You know who didn't? The one that had prey naiveté, that were more vulnerable to fox predation, and went extinct long before Wooster et al. came around to run their experiments. Classic survivorship bias.
April 17, 2025 at 2:13 AM
This means the species they studied had ample time to evolve to live in the presence of foxes. You know who didn't? The one that had prey naiveté, that were more vulnerable to fox predation, and went extinct long before Wooster et al. came around to run their experiments. Classic survivorship bias.
Finally, Wallach & Lundgren run a meta-analysis, which finds support for a negative correlation between fox and prey abundance! Yay!
Naturally, they downplay this and focus on the result for cats.
Naturally, they downplay this and focus on the result for cats.
April 17, 2025 at 2:13 AM
Finally, Wallach & Lundgren run a meta-analysis, which finds support for a negative correlation between fox and prey abundance! Yay!
Naturally, they downplay this and focus on the result for cats.
Naturally, they downplay this and focus on the result for cats.
We now get to the meat of the paper, the systematic review of papers. Wallach & Lundgren compiled lots of studies, classified them as "in support" or "not in support", divided them into three classes and tallied them per species. Here's the summary figure. And honestly, genuinely impressive work!
April 17, 2025 at 2:13 AM
We now get to the meat of the paper, the systematic review of papers. Wallach & Lundgren compiled lots of studies, classified them as "in support" or "not in support", divided them into three classes and tallied them per species. Here's the summary figure. And honestly, genuinely impressive work!
I'd actually like to start with this sentence from the discussion. I don't believe this claim - I think the author are very much trying to reject this hypothesis, and hiding behind "just asking questions". Keep this in mind as we go through the paper.
April 17, 2025 at 2:13 AM
I'd actually like to start with this sentence from the discussion. I don't believe this claim - I think the author are very much trying to reject this hypothesis, and hiding behind "just asking questions". Keep this in mind as we go through the paper.
We've also tried to sort out the slightly messy nomenclature used to describe head scales in the skinks of New Guinea and the region. We think many skink enthusiasts might find this a useful resource!
April 15, 2025 at 5:15 AM
We've also tried to sort out the slightly messy nomenclature used to describe head scales in the skinks of New Guinea and the region. We think many skink enthusiasts might find this a useful resource!
We suspect the species is arboreal because A) that's what Prasinohaema generally are, but more importantly B) the paratype was collected way up in a pandanus. Which might explain why we have so few observations. They're also found in much higher elevations than usual for Prasinohaema, 2175-2900m
April 15, 2025 at 5:13 AM
We suspect the species is arboreal because A) that's what Prasinohaema generally are, but more importantly B) the paratype was collected way up in a pandanus. Which might explain why we have so few observations. They're also found in much higher elevations than usual for Prasinohaema, 2175-2900m
Morphologically, it's quite unique, with an unusual head scalation (for a Prasinohaema) and very distinctive chequered colouration, both dorsally and ventrally
April 15, 2025 at 5:10 AM
Morphologically, it's quite unique, with an unusual head scalation (for a Prasinohaema) and very distinctive chequered colouration, both dorsally and ventrally
Queue Steve Richards who, in 2009, collected another specimen, our holotype, from the Muller Range, and photographed another specimen in Gigira Ridge. The new specimen allowed us to extract mitochondrial DNA, which unequivocally identifies it as a member of Prasinohaema
April 15, 2025 at 5:07 AM
Queue Steve Richards who, in 2009, collected another specimen, our holotype, from the Muller Range, and photographed another specimen in Gigira Ridge. The new specimen allowed us to extract mitochondrial DNA, which unequivocally identifies it as a member of Prasinohaema
The new species we described is Prasinohaema scurrula, and its nested inside the lineage we call Prasinohaema sensu stricto, which also includes the type species, P. flavipes, as well as P. prehensicauda
April 15, 2025 at 4:59 AM
The new species we described is Prasinohaema scurrula, and its nested inside the lineage we call Prasinohaema sensu stricto, which also includes the type species, P. flavipes, as well as P. prehensicauda
Prasinohaema is a genus of skinks mostly endemic to New Guinea. They are unique among amniotes in having green blood pigments, which colours their tissues bluish-greenish, as seen in this photo of the mouth of new species, Prasinohaema scurrula
April 15, 2025 at 4:54 AM
Prasinohaema is a genus of skinks mostly endemic to New Guinea. They are unique among amniotes in having green blood pigments, which colours their tissues bluish-greenish, as seen in this photo of the mouth of new species, Prasinohaema scurrula
New species alert!
🦎🧪
We (myself, Glenn Shea, Stephen Richards and Paul Oliver) just published a description of a fantastic new species of Prasinohaema from New Guinea. A short thread:
🦎🧪
We (myself, Glenn Shea, Stephen Richards and Paul Oliver) just published a description of a fantastic new species of Prasinohaema from New Guinea. A short thread:
April 15, 2025 at 4:51 AM
New species alert!
🦎🧪
We (myself, Glenn Shea, Stephen Richards and Paul Oliver) just published a description of a fantastic new species of Prasinohaema from New Guinea. A short thread:
🦎🧪
We (myself, Glenn Shea, Stephen Richards and Paul Oliver) just published a description of a fantastic new species of Prasinohaema from New Guinea. A short thread:
Even in amphibians, where 86% of species have larger females! This doesn't mean female-specific selection isn't important - we think fecundity selection is the reason why most amphibian species are female-biased. But selection on male size in specific lineages can break the class-wide pattern.
December 23, 2024 at 11:48 PM
Even in amphibians, where 86% of species have larger females! This doesn't mean female-specific selection isn't important - we think fecundity selection is the reason why most amphibian species are female-biased. But selection on male size in specific lineages can break the class-wide pattern.
This result is supported by phylogenetic generalised least squares models that show that SSD in mammals becomes more female-biased with greater decreases in male size, and SSD in amphibians becomes more male-biased with greater increases in male size.
December 23, 2024 at 11:45 PM
This result is supported by phylogenetic generalised least squares models that show that SSD in mammals becomes more female-biased with greater decreases in male size, and SSD in amphibians becomes more male-biased with greater increases in male size.
The main result is that changes in male size are more common across the board in lineages that are sexually dimorphic. This means that usually male-biased lineages are driven by increasing male size, but also female-biased lineages are often driven by *smaller males* rather than larger females!
December 23, 2024 at 11:43 PM
The main result is that changes in male size are more common across the board in lineages that are sexually dimorphic. This means that usually male-biased lineages are driven by increasing male size, but also female-biased lineages are often driven by *smaller males* rather than larger females!
There is a strong phylogenetic structure. Some clades, like owls or snakes, tend to be female-biased. Others, like bustards or carnivores, tend to be male-biased. And this phylogenetic structure allowed us to use cool macroevolutionary models to explore possible mechanisms behind this variation
December 23, 2024 at 11:35 PM
There is a strong phylogenetic structure. Some clades, like owls or snakes, tend to be female-biased. Others, like bustards or carnivores, tend to be male-biased. And this phylogenetic structure allowed us to use cool macroevolutionary models to explore possible mechanisms behind this variation
We looked at this by compiling body size data for over 11,000 #tetrapods, roughly a third of all species. Some patterns:
On average, mammals are male-biased, amphibians are strongly female-biased, and birds monomorphic. Most squamates are dimorphic, but similar proportions male- and female-biased.
On average, mammals are male-biased, amphibians are strongly female-biased, and birds monomorphic. Most squamates are dimorphic, but similar proportions male- and female-biased.
December 23, 2024 at 11:30 PM
We looked at this by compiling body size data for over 11,000 #tetrapods, roughly a third of all species. Some patterns:
On average, mammals are male-biased, amphibians are strongly female-biased, and birds monomorphic. Most squamates are dimorphic, but similar proportions male- and female-biased.
On average, mammals are male-biased, amphibians are strongly female-biased, and birds monomorphic. Most squamates are dimorphic, but similar proportions male- and female-biased.
Old Charles here thought it was sexual selection - males fighting other males for access to females need to be bigger and bigger. And while that's received some support, other mechanisms are also supported, including ecological conflict, bimodal niches, etc. So is any single mechanism stronger?
December 23, 2024 at 11:22 PM
Old Charles here thought it was sexual selection - males fighting other males for access to females need to be bigger and bigger. And while that's received some support, other mechanisms are also supported, including ecological conflict, bimodal niches, etc. So is any single mechanism stronger?
So, what's the deal with SSD? We know it's incredibly common - a lot of animals are sexually dimorphic, like this extreme example of a northern elephant seal (male in the middle, females around). But what's driven the evolution of this widespread phenomenon?
December 23, 2024 at 11:09 PM
So, what's the deal with SSD? We know it's incredibly common - a lot of animals are sexually dimorphic, like this extreme example of a northern elephant seal (male in the middle, females around). But what's driven the evolution of this widespread phenomenon?
Look at all these data!!!
December 12, 2024 at 3:10 AM
Look at all these data!!!
@callanalexander.bsky.social on birds in vineyards - heaps of native birds present, and using a cool combination of supervised and unsupervised machine learning models to overcome false positive issues in AI detection of bird calls
#ESAus2024
#ESAus2024
December 12, 2024 at 3:08 AM
@callanalexander.bsky.social on birds in vineyards - heaps of native birds present, and using a cool combination of supervised and unsupervised machine learning models to overcome false positive issues in AI detection of bird calls
#ESAus2024
#ESAus2024
Mike Kearney showing how to determine which koala traits are functional based on theory around heat exchange
#ESAus2024
#ESAus2024
December 10, 2024 at 11:44 PM
Mike Kearney showing how to determine which koala traits are functional based on theory around heat exchange
#ESAus2024
#ESAus2024
Awesome research showing that employing "teacher toads" right before a cane toad invasion can teach taste aversion to goannas, allowing them to persist in the landscape once the actual invasion front arrives
#ESAus2024
#ESAus2024
December 9, 2024 at 10:36 PM
Awesome research showing that employing "teacher toads" right before a cane toad invasion can teach taste aversion to goannas, allowing them to persist in the landscape once the actual invasion front arrives
#ESAus2024
#ESAus2024
There are many ways to make your code reproducible! Here are some by @daxkellie.bsky.social that I wasn't aware of to keep track of package versions in your R project (yikes)
#ESAus2024
#ESAus2024
December 9, 2024 at 5:43 AM
There are many ways to make your code reproducible! Here are some by @daxkellie.bsky.social that I wasn't aware of to keep track of package versions in your R project (yikes)
#ESAus2024
#ESAus2024