text: novomessor ensifer novomessor ensifer is a species of ant endemic to mexico . a member of the genus novomessor in the subfamily myrmicinae , it was first described by swiss entomologist auguste forel in 1899 . n. ensifer was originally a part of the genus aphaenogaster until a recent phylogenetic study concluded that novomessor was genetically distinct and should be separated . the ant is a medium - sized species , measuring 5 . 5 to 10 millimetres ( 0 . 2 to 0 . 4 in ) . the ant is ferruginous - colored in some certain parts of the body , and small workers ( ) in incipient colonies are noticeably different in color and body structure . n. ensifer is active throughout the day , where they forage on the ground and sometimes on low herbs . colonies are found under stones and other objects in tropical dry forests and pine - oak forests . these ants are solitary foragers and predominately feed on insects such as wasps and months . the only known predator of n. ensifer is the giant horned lizard ( phrynosoma asio ) . while nothing is known about its reproduction , nuptial flight may take place during spring or summer , where queens establish their nests under stones and other objects . taxonomy novomessor ensifer was originally described as aphaenogaster ensifera in 1899 by swiss entomologist auguste forel , who provided the first of n. ensifer in his third volume of - americana . among the genus aphaenogaster , italian entomologist carlo emery placed n. ensifer in the subgenus in 1915 , although this is now a synonym . in 1934 , the taxon novomessor manni was described as a new species of novomessor based on workers collected by william m. mann at colima , mexico . however , a study showed that n. manni was a synonym of n. ensifer . brown comments that n. manni was described as a new species because of the supposed distinct features between two type specimens of n. ensifer , but brown noticed no morphological differences . the exact type locality for n. manni is unknown , but entomologist paul speculates that the ant is restricted to arid scrub forests around the pacific slope in mexico . this speculation is consistent with the preferred habitat of n. ensifer . novomessor was synonymized in 1974 , although evidence to retain it as a valid genus emerged when scientists discovered an exocrine gastral glandular system in two novomessor species and none in aphaenogaster . however , n. ensifer does not have this glandular system . english myrmecologist barry bolton argues that basing the genus on such feature cannot justify the separation of novomessor and aphaenogaster . in 2015 , a phylogenetic study concluded that novomessor was genetically distinct from aphaenogaster , and the genus was revived from synonymy to include n. ensifer , n. albisetosus and n. as members of it . description n. ensifer is a medium - sized species , measuring 5 . 5 to 10 millimetres ( 0 . 2 to 0 . 4 in ) . excluding the mandibles , the head is 1 . 93 – 2 . 53 millimetres ( 0 . 076 – 0 . 100 in ) long and 1 . 25 – 1 . 69 millimetres ( 0 . 049 – 0 . 067 in ) wide . the scapes of the antennae surpass the occipital margin , and the second segment of the funiculus is longer than the first . the third and fourth segments are the same length as each other , although they are longer than the second . between the fifth and second last segments , they are much shorter except for the last one . the head is twice as long than broad , and it is widest behind the eyes . the larvae measure 8 millimetres ( 0 . 3 in ) in length and appear similar to that of n. albisetosus . the larvae can be distinguished by the abundance of hair with long stouts found on the body . the apical teeth of the mandibles are long and straight , whereas the medial teeth are much smaller . the posterior to the eyes are convex , where it converges towards the occiput ( the back of the head ) and forms a collar seen in several aphaenogaster species . the ants have large , triangular mandibles with three apical teeth and a flat clypeus . the eyes are large with 400 facets , but workers from small incipient colonies only have 200 facets . workers from incipient also differ from workers living in mature colonies , notably in size , body shape and coloration . the average length is 5 . 56 – 6 . 5 millimetres ( 0 . 219 – 0 . 256 in ) ; the head is 1 . 52 – 1 . 69 millimetres ( 0 . 060 – 0 . 067 in ) long and 0 . 98 – 1 . 12 millimetres ( 0 . 039 – 0 . 044 in ) wide . the spines ( spines found on the first abdominal segment that protect the pedicel ) are much shorter . hair is also less noticeable on the workers . the ant has pubescence ( soft short hair ) abundant throughout some certain parts of the body , including the funiculi and tarsi . it is more sparse on the coxae , genae ( an area on both sides of the head below the eyes ) , gaster and gula ( the reduced sternite of the first segment of the thorax ) . hairs on the scapes point downwards . erect and suberect hair are seen all over the body in sparse numbers , although this varies . these hairs are not as abundant in comparison to other novomessor species . the head and thorax are both ferruginous - colored , and the spines , legs and node are yellowish red . the antennal scapes are reddish brown and the abdomen is brown . the hair exhibits a gold - like color . the suture is absent from the thorax , and the mesonotum is wider than the epinotum . the front portion of the mesonotum is narrow whereas the back is rectangular . the node is evenly round and oval shaped , the postpetiole is narrow at the front and the dorsum is feebly convex . the gaster is large and oval shaped . distribution and habitat n. ensifer is endemic to mexico and can be found in tropical dry forests at altitudes of between 115 and 1 , 700 ft ( 35 and 518 m ) above sea level . in some cases , colonies have been found 5 , 000 ft ( 1 , 500 m ) below the pacific slope . the ant is found throughout several mexican states within the east , including guerrero and michoacán from the south , and colima and jalisco from the north . nests are commonly found in basins and mountains along the pacific slope in pine - oak forests . scrub - thorn forests are also abundant , consisting of trees and shrubs that are 15 and 25 ft ( 4 . 6 and 7 . 6 m ) tall , but other areas may contain low herbs and grasses . plants and trees such as thorn trees ( acacia ) , plants ( ) and casearia corymbosa have been identified in these habitats . other identified plants and trees include indian mallows ( ) , spurred ( cristata ) , erectum , ( commelina ) , cigar plants ( ) , hairy ( digitaria ) , crane grass ( unisetus ) , mimosa , mexican ( panicum ) , senna uniflora and setaria . these habitats usually have a wet season in summer and autumn and a dry season in spring . n. ensifer is a species that can thrive in dry climates . in colima , colonies are frequent among the basins , but rarely are they found in the mountainous regions . n. ensifer ants prefer to nest in the sand and under large stones , as certain areas in manzanillo had no stones buried in the soil and no colonies were found alongside hills with plain soil . most colonies are found under stones with no noticeable craters surrounding the nest entrance , although one colony was found under an acacia plant . these nest holes are usually 1 in ( 2 . 5 cm ) in diameter . a single path connects the entrance to the main nest site , followed by a passage that descends straight into the dirt several inches deep . this passage widens under a stone which forms a gallery for the larvae and pupae . wherever stones are formed , passageways may descend further into the ground and form more chambers . although it is unknown how deep these passages go , excavated nests are as deep as 15 in ( 38 cm ) . behavior and ecology unlike other novomessor species , workers forage early in the morning and late afternoon , whereas n. and n. albisetosus forage during the afternoon and evening . however , it is unknown whether or not these ants are active during the night . foragers first emerge from their nests at 9 a.m. and return by 5 p.m. they are rarely seen during the middle of the day when temperatures reach 95 – 100 ° f ( 35 – 38 ° c ) , although the ground temperature is considerably higher . workers are commonly seen foraging between 9 and 11 a.m. and 3 to 5 p.m. most workers forage on the ground , but sometimes they can be seen walking on low herbage without feeding on the plants or collecting any seeds . excavated nests showed no evidence that these ants collect seeds , and no workers were seen collecting them or carrying them back to the nest . n. ensifer ants are solitary foragers that work 25 ft ( 7 m ) away from their home nest . n. ensifer predominately feeds on insects they prey on , consuming dead insects such as ichneumon wasps , wasps and small moths . when a worker discovers a dead insect , it will start to pull and carry it back to the nest immediately , and other nestmates will join once they detect it . workers do not cooperate with each other and pull the insect from all directions , accidentally tearing it apart . however , the workers will eventually have a piece of the insect left and return it to the nest . the only known predator of n. ensifer is the giant horned lizard ( phrynosoma asio ) . mites and arthropods are known to dwell inside nests , but their function or purpose within a colony is unknown . nothing is known about its reproduction or nuptial flight . collectors note that no alates or pupae resembling alate forms were found in excavated colonies between august and february , and the larvae collected were not large enough to be reproductive ants . however , it is possible that nuptial flight takes place in spring or summer , and like n. albisetosus and , alates most likely start to occur by june . after nuptial flight , queens search for a suitable colony by building a chamber under objects such as stones and exposed roots of woody plants . this theory stated by entomologist paul is supported by the fact that these ants depend on stones buried in the soil for nest construction . the larvae and pupae are unsorted in the upper chambers of the nest that are joined together by hooked hairs on the side of the larvae . this arrangement most likely helps workers move the brood efficiently and keep them together in a group . colonies may only have 30 workers and brood in all life stages . unlike the larvae and pupae , the eggs and queen are not found in the uppermost galleries , but rather they are found in the deepest chambers of the nest . in large nests , small workers resembling the first generation of brood are either rare or absent .