{{Short description|Species of bat}} {{For|the family of bats commonly known as evening bats|Vesper bat}} {{speciesbox | name = Evening bat | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Solari, S. |date=2019 |title=''Nycticeius humeralis'' |volume=2019 |article-number=e.T14944A22015223 |doi=10.2305/IUCN.UK.2019-1.RLTS.T14944A22015223.en |access-date=19 November 2021}}</ref> | image = Nycticeius humeralis Evening bat.JPG | image_caption = | image_alt = A small bat is in the hands of a researcher | genus = Nycticeius | species = humeralis | authority = (Rafinesque, 1818) | range_map = Nycticeius humeralis map.svg | synonyms = }}
The '''evening bat''' ('''''Nycticeius humeralis''''') is a species of bat in the vesper bat family that is native to North America.<ref name="MSW3">{{MSW3 Chiroptera | id = 13801926 | page = }}</ref> Hunting at night, they eat beetles, moths, and other flying insects.
== Description == {{CSS image crop |Image = Evening bat.jpg |bSize = 250 |cWidth = 250 |cHeight = 200 |oTop = 150 |oLeft = 0 |Location=left |Description = An evening bat in the hands of a researcher |alt=A small bat with its mouth open is being held by a hand }}
The evening bat is a small bat weighing {{cvt|7|–|15|g}}<ref name="Wilkinson 1992" /> found throughout much of the midwestern and eastern United States. Their forearms are {{cvt|34|–|38|mm}} in length.<ref name="Watkins"/> The tip of each dorsal hair is a light gray, and one to two-thirds of the basal is dark brown. Though there have been some cases of white pelage, the majority of the population is mostly brown in color.<ref name="Watkins">Watkins, L. C. (1972). Nycticeius humeralis. Mammalian species, (23), 1-4.</ref> They have wide, dog-like muzzles, pronounced facial glands, and disproportionately large bacula.<ref name="Watkins"/><ref name="Hamilton 1949">{{cite journal | last1 = Hamilton | first1 = W. J. | year = 1949 | title = The bacula of some North American vespertilionid bats | journal = Journal of Mammalogy | volume = 30 | issue = 2| pages = 97–102 | doi=10.2307/1375254| pmid = 18121317 | jstor = 1375254 }}</ref> Evening bats can be mistaken for juvenile big brown bats, due to their physical resemblance but smaller size.
=== Morphology === Evening bats have relatively robust jaws, compared to other insectivorous bats.<ref name="Freeman 1981">{{cite journal | last1 = Freeman | first1 = P. W. | year = 1981 | title = Correspondence of food habits and morphology in insectivorous bats | url = http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1016&context=museummammalogy| journal = Journal of Mammalogy | volume = 62 | issue = 1| pages = 166–173 | doi=10.2307/1380489| jstor = 1380489 | s2cid = 12934993 | url-access = subscription }}</ref> They have an unkeeled calcar and a short, round tragus.<ref name="Barbour 1974">Barbour, R., W. Davis. 1974. Mammals of Kentucky. Kentucky: The University Press of Kentucky.</ref> The curvature of the tragus helps distinguish it from bats of the genus ''Myotis'', which otherwise look very similar.<ref name="Barbour 1974"/> Their skull has one upper incisor on each side with 4 molariform teeth.<ref>{{Cite book|title=Mammals of Indiana|last=Whitaker|first=John O.|publisher=Indiana University Press|year=2010|isbn=978-0-253-22213-8|location=Bloomington, IA|pages=118 & 119}}</ref>
==Biology== The evening bat is a relatively short-lived, especially compared to other bats in its geographic range.<ref name="Austad 2010">Austad, S. N. (2010). Cats,"rats," and bats: the comparative biology of aging in the 21st century. Integrative and comparative biology, icq131.</ref> It has a maximum age of 6 years, though few individuals live past 4 years.<ref name="Humphrey 1970">{{cite journal | last1 = Humphrey | first1 = S. R. | last2 = Cope | first2 = J. B. | year = 1970 | title = Population samples of the evening bat, Nycticeius humeralis | journal = Journal of Mammalogy | volume = 51 | issue = 2| pages = 399–401 | doi=10.2307/1378503| jstor = 1378503 }}</ref><ref name="Austad 2010"/> Its short lifespan for a bat could be explained by its considerably higher reproductive output. Bats that only have one pup per year would need to live much longer to have the same fitness as a shorter-lived species with two or three pups per year.<ref name="Austad 2010"/>
===Reproduction=== Evening bats mate in the fall and winter; the sperm is stored until the spring, when fertilization occurs.<ref name="Whitaker">Whitaker, J. O., Jr., J. B. Cope, D. W. Sparks, V. Brack, Jr., and S. Johnson. Bats of Indiana. Publication no. 1, ISU Center for North American Bat Research and Conservation. Indiana State University. 59 pp.</ref> Female bats form maternity colonies in May,<ref name="Watkins 1981">Watkins, L. C., & Shump Jr, K. A. (1981). Behavior of the evening bat Nycticeius humeralis at a nursery roost. American Midland Naturalist, 258-268.</ref> consisting of 15-300 individuals.<ref name="Wilkinson 1992"/> Of females that give birth, 90% have twins, but singletons and triplets are also possible.<ref name="Whitaker"/><ref name="Watkins 1981"/><ref name="Kurta 2005">Kurta, A., Foster, R., Hough, E., & Winhold, L. (2005). The evening bat (Nycticeius humeralis) on the northern edge of its range—a maternity colony in Michigan. The American midland naturalist, 154(1), 264-267.</ref> Though it is more common for evening bats to nurse their own offspring,<ref name="Wilkinson 1992">{{Cite journal|last=Wilkinson|first=G.S.|year=1992|title=Communal Nursing in the Evening Bat, Nycticeius humeralis|journal=Behavioral Ecology and Sociobiology|volume=31| issue = 4|pages=225–235|doi=10.1007/bf00171677|bibcode=1992BEcoS..31..225W |s2cid=15560376}}</ref> a small proportion of offspring are nursed by unrelated females. The pups are capable of flight within a month of birth.<ref name="Watkins 1981"/> Pups are weaned within 42 days of birth.<ref name="Wilkinson 1992"/> Female pups exhibit natal philopatry, meaning that as adults, they return to the roost where they were born to give birth.<ref name="Wilkinson 1992"/>
===Diet=== These bats have varied diets. A majority of the bats' diet in Indiana and Illinois are beetles, including the spotted cucumber beetle, which is a serious agricultural pest.<ref name="Whitaker 1992">Whitaker Jr, J. O., & Clem, P. (1992). Food of the evening bat Nycticeius humeralis from Indiana. American Midland Naturalist, 211-214.</ref> In southern Illinois, the spotted cucumber beetle is almost 25% of the evening bats' diet.<ref name="Feldhamer 1995">Feldhamer, G. A., Whitaker Jr, J. O., Krejca, J. K., & Taylor, S. J. (1995). Food of the evening bat (Nycticeius humeralis) and red bat (Lasiurus borealis) from southern Illinois. Transactions of the Illinois Academy of Science, 88, 139-143.</ref> Other beetles consumed include ground beetles and scarab beetles.<ref name="Whitaker 1992"/> Moths are also a significant dietary component.<ref name="Whitaker 1992"/> Bugs, winged ants, and flies are prey items of less significance.<ref name="Feldhamer 1995"/><ref name="Carter 2004"/> Evening bats partition resources with other insectivorous bats in their range, such as the eastern red bat and Seminole bat.<ref name="Carter 2004">Carter, T. C., Menzel, M. A., Chapman, B. R., & Miller, K. V. (2004). Partitioning of food resources by syntopic eastern red (Lasiurus borealis), Seminole (L. seminolus) and evening (Nycticeius humeralis) bats. The American midland naturalist, 151(1), 186-191.</ref> Despite foraging in the same areas at the same time, these three bat species choose different prey items at different points throughout the summer.<ref name="Carter 2004"/>
== Distribution== At first, the evening bat was thought of as a southeastern bat species.<ref name="Baker 1968">{{cite journal | last1 = Baker | first1 = W. W. | last2 = Marshall | first2 = S. G. | last3 = Baker | first3 = V. B. | year = 1968 | title = Autumn fat deposition in the evening bat (Nycticeius humeralis) | journal = Journal of Mammalogy | volume = 49 | issue = 2| pages = 314–317 | doi=10.2307/1377991| jstor = 1377991 }}</ref> However, breeding evening bats have been found as far north as Michigan and as far west as the 100th meridian.<ref name="Kurta 2005"/> Evening bats roost in a variety of structures, including Spanish moss, under bark, in tree cavities, and in buildings.<ref name="Menzel 2001">Menzel, M. A., Carter, T. C., Ford, W. M., & Chapman, B. R. (2001). Tree-roost characteristics of subadult and female adult evening bats (Nycticeius humeralis) in the Upper Coastal Plain of South Carolina. The American Midland Naturalist, 145(1), 112-119.</ref> For foraging habitat, evening bats in Georgia prefer pine forest, riparian zones, and open fields.<ref name="Morris 2011">{{cite journal | last1 = Morris | first1 = A. D. | last2 = Miller | first2 = D. A. | last3 = Conner | first3 = L. M. | year = 2011 | title = Home-range size of evening bats (Nycticeius humeralis) in southwestern Georgia | journal = Southeastern Naturalist | volume = 10 | issue = 1| pages = 85–94 | doi=10.1656/058.010.0107| s2cid = 84793982 }}</ref> Evening bats have home ranges of approximately 300 hectare (1.15 mi<sup>2</sup>).<ref name="Morris 2011"/> Because the evening bat is not found in the northernmost extent of its range in the winter, it is likely that at least some evening bats are migratory.<ref name="Watkins"/>
===Conservation=== While the evening bat is considered endangered in the state of Indiana,<ref name="INDNR">{{cite web |url=https://secure.in.gov/dnr/fishwild/8450.htm |title=Bats in Indiana |author=<!--Not stated--> |website=Indiana Department of Natural Resources |publisher=IN.gov |access-date=April 28, 2017}}</ref> it has a cosmopolitan distribution throughout the southeast and midwest.<ref name="Menzel 2001"/> Because evening bats do not enter or hibernate in caves, the species is not at-risk from white-nose syndrome, which has killed over six million bats in the United States since 2006.<ref name="JSen">{{cite news |last=Bergquist |first=Lee |date=September 13, 2016 |title=First find of bat species in 60 years |url=http://www.jsonline.com/story/news/local/wisconsin/2016/09/13/first-find-bat-species-60-years/90328140/ |work=Journal Sentinel |location=Milwaukee |access-date=April 28, 2017 }}</ref> The evening bat's avoidance of this disease, along with die-offs of many other species, is possibly responsible for the evening bat recently expanding its range into Wisconsin in 2015 and Minnesota in 2016.<ref name="JSen"/><ref name="MNDNR">{{cite news |author=<!--Staff writer(s); no by-line.--> |title=First new bat species discovered in Minnesota in more than a century |url=http://news.dnr.state.mn.us/2016/08/01/first-new-bat-species-discovered-in-minnesota-in-more-than-a-century/ |work=Minnesota DNR |location=Minnesota |date=August 1, 2016 |access-date=April 28, 2017 }}</ref> {| {{Table}} ! State !! Conservation Status |- ! Alabama | Lowest Conservation Concern |- ! Arkansas | Not listed |- ! Florida | Not listed |- ! Georgia | Not listed |- ! Illinois | Not listed |- ! Indiana | State Endangered |- ! Iowa | Not listed |- ! Kentucky | Threatened |- ! Kansas | Not listed |- ! Louisiana | Not listed |- ! Maryland | Not listed |- ! Michigan | Threatened |- ! Minnesota | Not listed |- ! Mississippi | Not listed |- ! Missouri | Not listed |- ! Nebraska | Not listed |- ! North Carolina | Not listed |- ! Ohio | Species of Special Interest |- ! Oklahoma | Not listed |- ! Pennsylvania | Not listed |- ! South Carolina | Not listed |- ! Tennessee | Not listed |- ! Texas | Not listed |- ! Virginia | Not listed |- ! West Virginia | Not listed |- ! Wisconsin | Not listed |}
==References== {{Reflist|30em}}
==External links== {{Commonscat-inline|Nycticeius humeralis|''Nycticeius humeralis''}} {{Wikispecies-inline|Nycticeius humeralis}}
{{Vespertilionidae|V.|N.}}
{{Taxonbar|from=Q1832323}}
Category:Nycticeius Category:Bats of North America Category:Bats of Mexico Category:Bats of the United States Category:Fauna of the Eastern United States Category:Fauna of the Plains-Midwest (United States) Category:Fauna of the Southeastern United States Category:Mammals described in 1818 Category:Taxa named by Constantine Samuel Rafinesque Category:Least concern biota of the United States