New paper: Insights into the assembly rules of a continent-wide multilayer network

How are ecological systems assembled? Identifying common structural patterns within complex networks of interacting species has been a major challenge in ecology, but past research has focused primarily on single interaction types aggregated in space or time. In this new study, our team shed light on the assembly rules of a multilayer network of frugivory and nectarivory interactions between bats and plants in the Neotropics. We described a massive network whose parts differ from the whole, or a compound structure that appears to be assembled by different processes –from evolutionary constraints to functional morphology– at various scales. You can read more about these exciting findings in our paper here, and a wonderful “behind the scenes” summary here.

The hierarchical assembly of a continent-wide, multilayer network of bats and plants (credit: Marco Mello).

Congratulations Dr. Stanchak!

Katie Stanchak successfully defended her Dissertation this past October! Katie’s research focused on the anatomical diversification and function of a skeletal novelty found in bat feet, the calcar. She conducted unprecedented comparative analyses of the calcar and associated structures across major bat groups, and experimental assays to better understand the function and developmental origin of the calcar. We are so proud of all she accomplished during her PhD, and excited about her postdoc plans to continue studying morphological and functional diversity in other vertebrate groups!

Congratulations to Dr. Kelly and Dr. Leiser-Miller!

Congratulations to the newly minted PhDs from the lab, Rochelle Kelly and Leith Leiser-Miller!! Both of them did a terrific job defending their dissertations last week. Rochelle’s research revealed geographic and ecological factors that affect the diversity, distribution, and activity of bats in the San Juan archipelago. Leith’s dissertation led to exciting discoveries about the acoustic diversity and sensory ecomorphology of phyllostomid bats . We are so proud of all the work they were able to accomplish!

Summer awards!

Congratulations to lab members receiving awards and grants this summer!

Katie Stanchak was awarded the American Society of Mammalogists’ Anna M. Jackson Award, which carries the honor of presenting her paper at the opening Plenary Session of the ASM meeting this year.

David Villalobos was awarded a Theodore Roosevelt Memorial Fund grant from the American Museum of Natural History to conduct field research on cricetid rodents in Costa Rica this summer.

PI Santana was awarded a Fulbright Scholars fellowship to expand upon her work on the coevolution between pepper plants and short-tailed fruit bats in Costa Rica, where she will be spending part of her sabbatical next year.

New paper!! Adaptive shifts in skull shape evolution in bats

An image of two bat skulls.
Skulls of a common blossom bat, Syconycteris australis (left) and a grey-headed flying fox, Pteropus poliocephalus(right).Dennis Wise/University of Washington

In a new and exciting paper in Nature Communications, we present the results of phylogenetic comparative analyses across hundreds of bat species, and demonstrate how two major forces –echolocation and diet– shaped the diversity of bat skulls over their evolutionary history. Check out this press release highlighting the main results of the paper, and the methods we used!

We’re moving – twice!

We are currently moving the Burke Museum’s ~55,000 mammal specimens to the New Burke, which will open in Fall 2019. The mammal collection is currently closed for operations, as we joyfully transport our specimens to this brand-new facility in the UW Seattle campus:

Our lab has also moved to the Life Sciences Building, a beautiful new facility designed to enhance collaboration across the UW Biology Department, and active-learning teaching efforts.

New Paper! Bat rabies in Washington State

In collaboration with the Washington Department of Health and the Centers for Disease Control, we  just published a new paper investigating spatial and temporal trends in rabies prevalence among Washington bats. We found that the highest number of positive rabies cases occur between July and August. We also found that how bats are encountered is significantly associated with rabies positivity. For example, dogs are more likely to catch a rabid bat than cats;  additionally, bats found outdoors are more likely to test positive for rabies than bats found inside a house.

We also found that rabies prevalence varied among species, ranging between 2-11% positive. However, because some species (e.g., Myotis spp.) look nearly identical, they are  commonly misidentified. This suggests that genetic barcoding may be necessary to accurately assess species-specific patterns.

Seasonal trends in the number of bat submitted for rabies testing in Washington State and how many test positive.

New paper: Primary productivity explains size variation across the Pallid bat’s western geographic range

Pallid bat skullWhy do some species have larger individuals in certain parts of their range?  In many animal species, body size tends to increase with latitude. This famous ecological pattern, known as Bergmann’s Rule, was originally thought to be an adaptation for heat conservation. However, several hypotheses have been proposed, such as resource availability, resistance to starvation, and heat dissipation. We evaluate which of these hypotheses best explain geographic size variation in the Pallid bat in our new paper (Kelly et al., in press). We also investigate potential consequences of size variation by testing whether skull shape (an indicator of bite performance) changes in tandem with size.

Our results suggest that primary productivity (a proxy for resource availability) and to a lesser extent, heat conservation, best explain size variation across the Pallid bat’s western range. We also found that larger individuals have cranial traits associated with greater bite force production. This may help explain why larger individuals tend to consume larger and harder prey. Our results suggest that resource availability is a major factor explaining size, morphology, and possibly feeding performance in a wide-ranging and omnivorous bat species.

New paper on the hindlimb membrane musculature of bats

Virtual dissections in ventral view of the calcar-depressor muscle complex of one hindlimb of (a) Myotis californicus, (b) Molossus molossus, and (c) Artibeus jamaicensis.

Ph.D. student Katie Stanchak just published a new paper describing  the variation in the membrane and limb musculature associated with the calcar – a neomorphic skeletal structure found in the hind limbs of most bats. By combining diffusible iodine-based contrast enhanced computed tomography (diceCT) and standard histological techniques, Katie found that the arrangement of the calcar musculature varies among bat species that have different flight ecologies. These results suggest that the calcar may have a functional role in flight maneuverability, an idea that Katie will be testing in later stages of her Dissertation.

Katie’s article has also been featured in the diceCT blog.

More papers! Behavioral correlates of cranial muscle functional morphology

Check out the new issue of the Anatomical Record, co-edited with Adam Hartstone-Rose and Damiano Marchi! It is full of anatomical goodness, and showcases new findings and cutting-edge techniques in the study of muscle functional morphology. This issue contains several papers by Santana lab members:

Curtis A.A. and Santana S.E. 2018. Jaw-dropping: functional variation in the digastric muscle in bats. The Anatomical Record 301: 279–290. PDF

Santana S.E. 2018. Comparative anatomy of bat jaw musculature via Diffusible Iodine-Based Contrast-Enhanced Computed Tomography. The Anatomical Record 301: 267–278. PDF

Hartstone-Rose and Santana S.E. 2018. Behavioral correlates of cranial muscle functional morphology. The Anatomical Record 301: 197–201. PDF

Arbour J.A. and López-Fernández H. 2018. Intrinsic Constraints on the Diversification of Neotropical Cichlid Adductor Mandibulae Size. The Anatomical Record 301: 216–226.