All You Can Eat: High Performance Capacity and Plasticity in the Common Big-Eared Bat, Micronycteris microtis (Chiroptera: Phyllostomidae)

Ecological specialization and resource partitioning are expected to be particularly high in the species-rich communities of tropical vertebrates, yet many species have broader ecological niches than expected. In Neotropical ecosystems, Neotropical leaf-nosed bats (Phyllostomidae) are one of the most ecologically and functionally diverse vertebrate clades. Resource partitioning in phyllostomids might be achieved through differences in the ability to find and process food. We selected Micronycteris microtis, a very small (5–7 g) animalivorous phyllostomid, to explore whether broad resource use is associated with specific morphological, behavioral and performance traits within the phyllostomid radiation. We documented processing of natural prey and measured bite force in free-ranging M. microtis and other sympatric phyllostomids. We found that M. microtis had a remarkably broad diet for prey size and hardness. For the first time, we also report the consumption of vertebrates (lizards), which makes M. microtis the smallest carnivorous bat reported to date. Compared to other phyllostomids, M. microtis had the highest bite force for its size and cranial shape and high performance plasticity. Bite force and cranial shape appear to have evolved rapidly in the M. microtis lineage. High performance capacity and high efficiency in finding motionless prey might be key traits that allow M. microtis, and perhaps other species, to successfully co-exist with other gleaning bats

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc

Regression of size-adjusted bite force on cranial morphology for <i>Micronycteris microtis</i> and other phyllostomids.

<p>Principal Component (PC) 1 was derived from ten linear measurements from dry skulls of M. microtis (N  =  6) and 29 phyllostomid species. PC1 explained most of the variation in bite force (R² = −0.247, F_1,30  =  10.63, P  =  0.0029). Bite force data for other phyllostomids from Santana & Dumont <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028584#pone.0028584-Santana1" target="_blank">[21]</a>.</p

<i>Micronycteris microtis</i> consuming a katydid.

<p>This image illustrates the relatively large size of some prey items included in the diet of this bat (Photo by Christian Ziegler).</p

Characteristics of the prey items and feeding behavior of <i>Micronycteris microtis</i>.

<p>Shallow unilateral bites are not indicated as these were very rarely used. Sample sizes for hardness of prey items are as follows: beetles: 139; cicadas: 2; dragonflies: 1; katydids: 29; roaches: 2; stick insects: 3. <i>M. microtis</i> maximum bite force is 8.25±1.5 N.</p

Behavioral and performance plasticity in phyllostomid bats while feeding on soft and hard prey items (fruits or insects).

<p>Species included for comparison are frugivores: Artibeus jamaicensis, Artibeus phaeotis, Carollia perspicillata, Centurio senex, Platyrrhinus helleri, Sphaeronycteris toxophyllum, Sturnira lilium and Uroderma bilobatum; insectivore: <i>Mimon crenulatum</i>; insectivore with carnivory (animalivory): <i>Tonatia saurophila</i>; omnivores: Carollia brevicauda, Glossophaga soricina, Phylloderma stenops, Phyllostomus discolor; omnivore with carnivory: <i>Phyllostomus hastatus</i>. (R²  =  0.684, F_1,14  =  9.3679, P  =  7.738exp-05).</p

Video snapshot of a group of three <i>Micronycteris microtis</i>, as observed in the roost in Barro Colorado Island, Panama.

<p>The individual in the center on the back of the group is eating a lizard.</p

Results from Analyses of Variance testing the effect of type of prey on the feeding behavior of <i>Micronycteris microtis</i>, (a) Effect of ‘prey type’ (from Table 1) on the percentage of bite types (shallow unilateral, shallow bilateral, deep unilateral, deep bilateral), and (b) Effect of ‘prey type’ (from Table 1) on the total number of bites used to eat a prey item, with prey length as a covariate.

<p>Results from Analyses of Variance testing the effect of type of prey on the feeding behavior of <i>Micronycteris microtis</i>, (a) Effect of ‘prey type’ (from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028584#pone-0028584-t001" target="_blank">Table 1</a>) on the percentage of bite types (shallow unilateral, shallow bilateral, deep unilateral, deep bilateral), and (b) Effect of ‘prey type’ (from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028584#pone-0028584-t001" target="_blank">Table 1</a>) on the total number of bites used to eat a prey item, with prey length as a covariate.</p

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.William F. Laurance, D. Carolina Useche, Julio Rendeiro, Margareta Kalka, Corey J. A. Bradshaw, Sean P. Sloan, Susan G. Laurance, Mason Campbell, Kate Abernethy, Patricia Alvarez, Victor Arroyo-Rodriguez, Peter Ashton, Julieta Benítez-Malvido, Allard Blom, Kadiri S. Bobo, Charles H. Cannon, Min Cao, Richard Carroll, Colin Chapman, Rosamond Coates, Marina Cords, Finn Danielsen, Bart De Dijn, Eric Dinerstein, Maureen A. Donnelly, David Edwards, Felicity Edwards, Nina Farwig, Peter Fashing, Pierre-Michel Forget, Mercedes Foster, George Gale, David Harris, Rhett Harrison, John Hart, Sarah Karpanty, W. John Kress, Jagdish Krishnaswamy, Willis Logsdon, Jon Lovett, William Magnusson, Fiona Maisels, Andrew R. Marshall, Deedra McClearn, Divya Mudappa, Martin R. Nielsen, Richard Pearson, Nigel Pitman, Jan van der Ploeg, Andrew Plumptre, John Poulsen, Mauricio Quesada, Hugo Rainey, Douglas Robinson, Christiane Roetgers, Francesco Rovero, Frederick Scatena, Christian Schulze, Douglas Sheil, Thomas Struhsaker, John Terborgh, Duncan Thomas, Robert Timm, J. Nicolas Urbina-Cardona, Karthikeyan Vasudevan, S. Joseph Wright, Juan Carlos Arias-G., Luzmila Arroyo, Mark Ashton, Philippe Auzel, Dennis Babaasa, Fred Babweteera, Patrick Baker, Olaf Banki, Margot Bass, Inogwabini Bila-Isia, Stephen Blake, Warren Brockelman, Nicholas Brokaw, Carsten A. Brühl, Sarayudh Bunyavejchewin, Jung-Tai Chao, Jerome Chave, Ravi Chellam, Connie J. Clark, José Clavijo, Robert Congdon, Richard Corlett, H. S. Dattaraja, Chittaranjan Dave, Glyn Davies, Beatriz de Mello Beisiegel, Rosa de Nazaré Paes da Silva, Anthony Di Fiore, Arvin Diesmos, Rodolfo Dirzo, Diane Doran-Sheehy, Mitchell Eaton, Louise Emmons, Alejandro Estrada, Corneille Ewango, Linda Fedigan, François Feer, Barbara Fruth, Jacalyn Giacalone Willis, Uromi Goodale, Steven Goodman, Juan C. Guix, Paul Guthiga, William Haber, Keith Hamer, Ilka Herbinger, Jane Hill, Zhongliang Huang, I Fang Sun, Kalan Ickes, Akira Itoh, Natália Ivanauskas, Betsy Jackes, John Janovec, Daniel Janzen, Mo Jiangming, Chen Jin, Trevor Jones, Hermes Justiniano, Elisabeth Kalko, Aventino Kasangaki, Timothy Killeen, Hen-biau King, Erik Klop, Cheryl Knott, Inza Koné, Enoka Kudavidanage, José Lahoz da Silva Ribeiro, John Lattke, Richard Laval, Robert Lawton, Miguel Leal, Mark Leighton, Miguel Lentino, Cristiane Leonel, Jeremy Lindsell, Lee Ling-Ling, K. Eduard Linsenmair, Elizabeth Losos, Ariel Lugo, Jeremiah Lwanga, Andrew L. Mack, Marlucia Martins, W. Scott McGraw, Roan McNab, Luciano Montag, Jo Myers Thompson, Jacob Nabe-Nielsen, Michiko Nakagawa, Sanjay Nepal, Marilyn Norconk, Vojtech Novotny, Sean O'Donnell, Muse Opiang, Paul Ouboter, Kenneth Parker, N. Parthasarathy, Kátia Pisciotta, Dewi Prawiradilaga, Catherine Pringle, Subaraj Rajathurai, Ulrich Reichard, Gay Reinartz, Katherine Renton, Glen Reynolds, Vernon Reynolds, Erin Riley, Mark-Oliver Rödel, Jessica Rothman, Philip Round, Shoko Sakai, Tania Sanaiotti, Tommaso Savini, Gertrud Schaab, John Seidensticker, Alhaji Siaka, Miles R. Silman, Thomas B. Smith, Samuel Soares de Almeida, Navjot Sodhi, Craig Stanford, Kristine Stewart, Emma Stokes, Kathryn E. Stoner, Raman Sukumar, Martin Surbeck, Mathias Tobler, Teja Tscharntke, Andrea Turkalo, Govindaswamy Umapathy, Merlijn van Weerd, Jorge Vega Rivera, Meena Venkataraman, Linda Venn, Carlos Verea, Carolina Volkmer de Castilho, Matthias Waltert, Benjamin Wang, David Watts, William Weber, Paige West, David Whitacre, Ken Whitney, David Wilkie, Stephen Williams, Debra D. Wright, Patricia Wright, Lu Xiankai, Pralad Yonzon & Franky Zamzan