Dr. Erin Brandt

Really excited to be starting as an Assistant Professor of Biomedical Sciences at Grand Valley State University! Looking forward to get back to teaching and starting an undergrad-focused research program asking questions about how spiders move and communicate! Watch this space for updates!

Huh, that is both alarming and interesting. I've definitely said my (very much captive-bred) ball python probably couldn't survive in the wild due to being a pampered house-snake. But arguing that about a spider is...wild.

The "dangerous situations" being...the wild?

Really nice image! I have a pinned box full of those flies. Very far on the backburner is a project to write up which species I found them in! Apparently we found a couple novel hosts for this species. We should chat at some point about maybe joining forces!

Yes please! That is gorgeous!

Holy crow! What spider species is this?

She's gorgeous!

Screengrab of a video showing a spider jumping. Spider is in the middle of the jump, in midair.

After an amazing day at the Georgia Aquarium, excited for #SICB2025 to get underway! I'll be speaking about jumping spider locomotion, and why it's weird (and cool) on Tuesday the 7th in the "Moving on Up" session at 10:30 am. Lots of great talks in that session!

I've been hesitating on knitting my first sweater, but this one looks worth the effort! Beautiful work!

Any of my SICB pals going this year who might want to spend a day at the Georgia Aquarium? Planning to spend the day of the 6th at the aquarium, and I may be able to get a second discounted ticket!

Salticid behaviorist/biomechanist at your service!

We've been calling it an "acoustic aid", since the definition of "tool" is pretty specific. But that's the gist!

Again, big thanks and congrats to my co-authors Natasha Mhatre @natashamhatre.bsky.social
Sarah Duke and Linda Wang. I may follow up with another thread about the process of data collection for this project. It was a truly heroic effort by our dedicated students!

At the end of the day, our pandemic-era work-from-home modelling project about crickets made us rethink something fundamental about acoustic ecology. We're thrilled by the new questions, hypotheses, and avenues of research now open to us.

Why was this missed for so long? Animal acoustics research has focused on sound propagation by comparing sound levels across distance. Our work focuses on the relationship between calling effort (vibrational velocity) to sound output. The gains that we found happen at a stage before propagation.

Acoustics theory from as far back as the 50s actually suggests that a hard surface can indeed increase sound radiation efficiency. This should also be true for dipoles (wings moving back and forth like crickets) and monoples (making sound from a voicebox, like wolves and frogs)

This is surprising! “Ground = good” is not the prevailing idea in the world of animal communication. The ground is usually thought to be an impediment. So this got us thinking, could “ground = good” be true for *all* singing animals?

But things get interesting looking at ground callers. Gryllus veletis is a field cricket that we know calls from the ground. Sure enough, this species stands to gain more efficiency from singing on the ground as they would from using a baffle.

Plot showing difference in sound radiation efficiency across species between three different calling strategies.

First, let’s look at Oecanthus henryi, a famous baffle-builder that we know stands to gain a lot of efficiency from baffle use. Sure enough, our models suggest that they would do much better with a baffle than calling from the ground.

If calling from the ground can increase efficiency, let’s answer our original question: does the calling environment provide alternatives to baffling that are equal or better than baffling? Let’s look at a couple examples:

Calling from the ground seems to have higher efficiencies overall. We didn’t expect this!

Being 1m off the ground is almost identical to open air. Things get messier calling from the ground. Instead of smooth, broad peaks and valleys, we see small, choppy features. The "ground effect" is thought to impede females in localizing mates BUT…

What we ended up with, is…well, a *lot* of data. Specifically a bunch of landscapes of efficiency across the acoustic-morphospace for different scenarios. See the paper for the full story, but here are some highlights...

To make the models more realistic, we used boundary element modeling to add a ground. We varied caller height above the ground (0, 0.05, 0.5, and 1 m). We ran these models for our entire acoustic morphospace: 0.4mm^2 to 4000 mm^2 and 500 Hz to 10000 Hz. That’s a total of 5304 different combinations.

Plot showing acoustic efficiency of all meaured species of crickets in ideal conditions.

Lo and behold, all measured crickets would gain efficiency with a baffle. The red line shows the optimal radiator size for every frequency of call (equivalent to using a baffle). The entire cricket acoustic-morphospace is left of the line! But this is under ideal conditions...

Next, we made models to determine the efficiency of sound radiation across the acoustic-morphospace, with and without a baffle. We used finite element methods first, with wings suspended in a sphere of air. Here's some of those sound fields for different size/freq combinations.

Plot showing distribution of species of a given wing size and call frequency.

With these data, we were able to determine the acoustic-morphospace of radiator size and call frequency that most crickets should occupy.

We first defined the acoustic-morphospace of crickets. Efficiency of sound radiation (how loud you are) is determined by size of the radiator (wings) and frequency of call We found these values for 112 species across 7 clades. royalsocietypublishing.org/doi/10.1098/...

But only a few species use baffles. With over 7000 species of crickets out there, why doesn’t everyone baffle? We hypothesized that maybe there’s something about the singing environment of most crickets that makes baffling less worthwhile.

In fact, baffles increase efficiency a lot – up to 10 dB. And previous work showed that crickets are so skilled at making them, they function almost optimally. In fact, it’s been argued that cricket baffles satisfy the criteria of manufactured tools!https://doi.org/10.1111/eth.12773