The bicolored trailing ant, or flower ant, (Monomorium floricola), is a minute light brown ant with an elongated body, distinctly bi-colored with a black head and abdomen. It probably originated in the tropical Asia, but through human commerce is now established throughout the tropics and sub-tropics world wide, nesting in bushes and trees. It also commonly inhabits homes in urban areas, even in temperate climates and as far north as Alaska. This arboreal species eats insect eggs as well as insects, living or dead, tends aphids, mealybugs and other honeydew-producing insects, and visits extra-floral nectaries and flowers for nectar. Like its sibling species, the Pharoah ant (M. pharoanis), its nests contain multiple queens, and it forms new colonies by budding of its population. A slow moving and cryptic ant, it is usually considered a minor pest despite its world-wide abundance, and appears to be able to co-exist with other ant species, perhaps due to its small size. It may have more of an impact on ecosystems than is currently assessed, because its presence is often overlooked.
This species is very common and occurs in and around houses and in low second growth vegetation almost anywhere in the country where ants occur. It nests opportunistically in any small cavity, usually in the low arboreal zone, and may become a house pest. Almost all the nests I have observed have been polygynous, with up to 7 dealate queens.
(No. 27 a a 27 f). . Cosmopolite dans les tropiques.
(27). Common locally about houses, not far from sealevel. Formicarium made in crevices of walls, & c. The workers. are diurnal (perhaps nocturnal also). They are attracted by sweet substances, and by dead animal matter; when they find these they remain a long time to feed, but appear to carry nothing away. It would seem that the females came out to forage with the workers, or alone. I have found them on tables, & c.
The workers move about singly, or four or five follow each other in a line; they cannot walk rapidly.
N. B. - Differs from No. 10 not only in colour, but in the proportion of joints ofthe antenna.
(27 a). About the house at Golden Grove (leeward), 800 ft. October. Many were found on' a bird-skin, which was in course of drying.
(27 b). Golden Grove, Nov. 9 th; evening. Crawling on a table. It was not attended by workers.
(27 c). Note lost. Probably from the same formicarium.
(27 d). Golden Grove Estate (leeward), 300 ft. Dec. 14 th. Formicarium found in a package of glass collection bottles or tubes, which had been packed away on a shelf in a dark corner. The ants had made their way through the cork stoppers of two of the tubes, and in these tubes they kept the larvas. In one of the bottles were numerous wingless females and. a few males; in another there were also winged females. The paper in which the tubes were wrapped was also full of ants, including numerous males and females. The colony must have consisted of at least five thousand ants. The number of wingless females was remarkable, the proportion to workers found in the nest being, I should suppose, one to ten or twelve; but a portion of the workers may have been out foraging. Only a small number comparatively of the different forms were saved. There were few larvae and pupae; males very numerous.
(27 e). Near Kingstown; open valley, 500 ft. Oct. 27 th. A female found alone under a log.
(27 f). Windward side; bank near the seashore, north of Georgetown; under a stone. Jan. 3 rd. Several nests of this species were found on the windward side.
These ants are often found in water-jars. Whether alive or dead, they always float on the surface of the water, if washed into it.
Monomorium floreanum StitzHNS 1932:68, fig. 1 (). Syntype s, s, Galapagos Isl., Floreana [whereabouts of type material unknown]. Syn. under M. floricola (Jerdon)HNS : Linsley and Usinger 1966:75.
Monomorium (Monomorium) angusticlava DonisthorpeHNS 1947:89. Syntype s (lectotype here designated from CAS material), Irian Jaya: Maffin Bay (CAS, BMNH) [examined]. Syn. under M. floricola (Jerdon)HNS : Bolton 1987:88.
Material examined.- M. specularisHNS : Lectotype: Two workers from Upolu, Samoa, G. Mayr Collection (NMW), may include one or both of the two syntype workers from the same locality mentioned in Mayr"s publication of M. specularisHNS . Label data indicates that these specimens were held by the Godeffroy Museum (stated as the repository for the type material by Mayr). Although the label data does not include the word "type" or its equivalent, I am designating a lectotype to fix the name for the species, as these specimens agree closely with the description of M. specularisHNS , and the issue of type status in view of the paucity of available data is otherwise unlikely to be resolved definitively. Paralectotype: , data as above (NMW). M. impressumHNS : Lectotype: , Rodriguez Island, Gulliver (publ. name of collector) (BMNH). The lectotype is designated to fix the name impressumHNS for populations of putative M. floricolaHNS in which the queen has a dark head and gaster and a very pale mesosoma. The lectotype is on a card rectangle including a second queen and a male, and is the queen on the LHS (seen from the rear). Paralectotypes: One queen and one male on the same card rectangle as the lectotype (BMNH). No attempt has been made to separate these ants. M. angusticlavaHNS : Lectotype: The California Academy of Science (CAS) possesses a specimen which bears a red bordered circle reading "type". The material received from the BMNH is mounted on pins bearing yellow bordered circles reading "paratype". However, Donisthorpe specifically states that he used sixteen workers in describing M. angusticlavaHNS , so there can be no assumption of a holotype. Since all specimens have the same collecting data, they should be treated as syntypes. I have selected the CAS specimen as a typical worker for this taxon, as it is described. A second worker appears to have been included on the same point, but has been largely destroyed, leaving a postpetiole and gaster. The lectotype details are: , Maffin Bay, Dutch New Guinea (Irian Jaya), E.S. Ross, viii 1944 (CAS). The choice of a lectotype fixes the name for this taxon, which was thought by Donisthorpe to be generally more gracile than M. floricolaHNS . Paralectotypes: Two pins (12 and 11) of pointed workers and one pin of two separately carded workers. Collection data exactly as for lectotype(BMNH).
Other material examined: Prov. Antsiranana: 18 km N Antalaha, Ampahana, Gary D. Alpert (1 ) (MCZ); Nosy Be, Ambatoloaka, 12.viii.1992 Alpert et al. (1 ) (MCZ). Prov. Mahajanga: P.N. Namoroka, 17.8 km 329 NW Vilanandro 8-12.xi.2002 BL. Fisher (1 ); P.N. Namoroka, 16.9 km 317 NW Vilanandro 12-16.xi.2002 BL. Fisher (1 ); P.N. Tsingy de Bemaraha, 3.4 km 93 E Bekopaka 6-10.xi.2001 (2 ). Prov. Toamasina: 9.7 km NNE Mahalevona 12.xii.1993 BL. Fisher (1 ); Mahavavy River, 6.2 km 145 SE Mitsinjo 1-5.xii.2002 BL. Fisher (12). Prov. Toliara: Beza-Mahafaly ["Mahafely"], 27 km E Betioky 23.iv.1997 BL. Fisher (1 ); Foret Mite, 20.7 km 29 WNW Tongobory 27.ii-3.iii.2002 BL. Fisher (4 ).
Worker description.- Head: Head rectangular; vertex planar or weakly concave; frons shining and smooth except for piliferous pits; pilosity of frons a mixture of well-spaced, distinctly longer erect and semi-erect setae interspersed with shorter decumbent setae or setulae. Eye moderate, eye width 1-1.5x greatest width of antennal scape; (in full-face view) eyes set above midpoint of head capsule; (viewed in profile) eyes set around midline of head capsule; eye elongate; Antennal segments 12; antennal club three-segmented. Clypeal carinae always well-defined; anteromedian clypeal margin emarginate, clypeal carinae terminating in small denticles; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin approximately level with antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes straight, parallel. Psammophore absent. Palp formula 1,2. Mandibular teeth three, plus minute, basal denticle or angle; mandibles with sub-parallel inner and outer margins, smooth (except for piliferous pits); masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth a small to minute denticle or angle, much smaller than t3 (four teeth present).
Mesosoma: Promesonotum shining and mainly smooth, striolae, if present, usually vestigial and confined to lower anterior mesopleuron, in some populations entire lower mesopleuron distinctly striolate; (viewed in profile) anterior promesonotum smoothly rounded, thereafter more-or-less flattened, promesonotum on same plane as propodeum; promesonotal setae seven to twelve; standing promesonotal setae consisting of well-spaced, incurved, erect and semi-erect setae only; appressed promesonotal setulae few, mainly on sides of promesonotum. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum shining and smooth, with multiple hair like striolae on metapleuron; propodeal dorsum convex; propodeum always smoothly rounded; standing propodeal setae consisting of one prominent pair anteriad, with other shorter setae very sparse or absent; appressed propodeal setulae very sparse or absent; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle absent or not visible. Propodeal lobes present as vestigial flanges or small strips of cuticle only.
Petiole and postpetiole: Petiolar spiracle lateral and situated within anterior sector of petiolar node; node (viewed in profile) evenly tumular to roundly conical; appearance of node shining and smooth throughout; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 1:1 and 3:4; anteroventral petiolar process absent or vestigial; ventral petiolar lobe absent; height ratio of petiole to postpetiole between 4:3 and 1:1; height -length ratio of postpetiole about 1:1; postpetiole shining and smooth; postpetiolar sternite without anterior lip or carina, or this structure vestigial.
Gaster: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few short, appressed setulae.
General characters: Color head, gaster brown, mesosoma tawny yellow or variegated yellow-and-brown, appendages yellow or yellowish-brown. Worker caste monomorphic.
Lectotype measurements ( M. specularisHNS ): HML 1.09 HL 0.42 HW 0.33 CeI 77 SL 0.28 SI 86 PW 0.20.
Lectotype measurements ( M. angusticlavaHNS ): HML 1.15 HL 0.43 HW 0.34 CeI 79 SL 0.29 SI 87 PW 0.21.
Other worker measurements: HML 1.00-1.21 HL 0.39-0.43 HW 0.31-0.34 CeI 79-85 SL 0.27-0.31 SI 81-90 PW 0.20-0.23 (n=19).
Queen description.- Head: Head rectangular; vertex weakly concave or planar; frons shining and smooth except for piliferous pits and striolae around antennal sockets, frontal carinae and below the eyes; frons a mixture of well-spaced, distinctly longer erect and semi-erect setae interspersed with shorter setae or setulae, which are decumbent or appressed, longer setae thickest on vertex. Eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin; (in full-face view) eyes set at about midpoint of head capsule; (viewed in profile) eyes set around midline of head capsule.
Mesosoma: Anterior mesoscutum smoothly rounded, thereafter more-or-less flattened; pronotum, mesoscutum and mesopleuron shining and mainly smooth, vestigial striolae, if present, confined to anterior katepisternum; length -width ratio of mesoscutum and scutellum combined about 2:1. Axillae narrowly separated (i.e., less than width of one axilla). Standing pronotal/mesoscutal setae a mixture of well-spaced, distinctly longer, erect and semi-erect setae which are curved distally, interspersed with much shorter, incurved, decumbent setae; appressed pronotal, mescoscutal and mesopleural setulae few, mainly on sides of pronotum and mesopleuron. Propodeum shining and smooth, metapleuron with a few distinct striolae; propodeum always smoothly rounded; propodeal dorsum convex; standing propodeal setae consisting of up to a dozen or more longer erect and shorter sub-erect setae; appressed propodeal setulae well-spaced and sparse; propodeal spiracle nearer metanotal groove than declivitous face of propodeum; propodeal lobes present as vestigial flanges only, or absent.
Wing: Wing not seen (queens dealated).
Petiole and postpetiole: Petiolar spiracle lateroventral and situated within anterior sector of petiolar node; node, in profile conical, vertex rounded; appearance of node shining and smooth; ratio of greatest node breadth to greatest node width about 1:1. Anterior petiolar process absent or vestigial; height ratio of petiole to postpetiole about 1:1; height -length ratio of postpetiole between 3:2 and 4:3; postpetiole shining and smooth; postpetiolar sternite without anterior lip or carina, or this structure vestigial.
Gaster: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.
General characters: Color head, gaster brown, mesosoma and nodes yellowish. Brachypterous alates not seen. Ergatoid or worker-female intercastes not seen.
Lectotype measurements ( M. impressumHNS ): HML 1.88 HL 0.72 HW 0.59 CeI 81 SL 0.60 SI 103 PW 0.42.
Other Queen measurements: HML 1.75-1.88 HL 0.54-0.55 HW 0.44-0.46 CeI 82-85 SL 0.39-0.40 SI 85-89 PW 0.31-0.33.
Male description.- Head: Head width -mesosoma width ratio between 4:3 and1:1; frons smooth to finely striolate. Compound eyes protuberant and elliptical; margin of compound eye margin of compound eye nearly abutting clypeus. Ocelli weakly turreted. Ratio of length of first funicular segment of antenna to second funicular segment between 3:4 and 2:3. Maximum number of mandibular teeth and denticles three.
Mesosoma: Mesoscutum broadly convex; pronotum and mesoscutum shining and mainly smooth, vestigial striolae, if present, confined to anterior katepisternum. Parapsidal furrows vestigial or absent; notauli absent. Axillae narrowly separated (i.e., less than width of one axilla).
Wing: Wing veins predominantly depigmented, with distal segments reduced to vestigial lines; vein m -cu absent; vein cu -a absent.
Petiole and postpetiole: Petiolar spiracle lateral and situated within anterior sector of petiolar node. Petiolar node, (viewed in profile) conical, vertex rounded; appearance of node shining and smooth; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 4:3 and 1:1. Anterior petiolar process absent or vestigial. Height ratio of petiole to postpetiole between 4:3 and 1:1; height -length ratio of postpetiole between 2:1 and 3:2; postpetiole shining and microreticulate.
Gaster: Pilosity of first gastral tergite consisting of well-spaced, semi-erect setae interspersed with a few appressed setulae.
General characters: Color uniformly brown.
Male measurements: HML 1.68 HL 0.46 HW 0.50 CeI 109 SL 0.16 SI 0.32 PW 0.44.
Remarks.- Workers of this species bear a striking resemblance in appearance and morphology to dark-headed, bicolored specimens of Monomorium termitobiumHNS , but can be distinguished by the combination of a uniformly dark brown or chocolate head and gaster. In M. termitobiumHNS the gaster is not uniformly dark brown or black, although it may be a dingy brownish-yellow or yellow with dark infuscation. The petiolar node in all Malagasy specimens of M. floricolaHNS that I have seen is also very low and broadly conical to tumular, barely higher than the postpetiole. The ventral surface of the petiole lacks a lobe of any description. Monomorium termitobiumHNS workers possess a petiolar node that is distinctly higher than the postpetiole, even when it is low conical in shape, and a subpetiolar lobe of varying degrees is always present.
Monomorium floricolaHNS , an exotic introduction, has been collected throughout Madagascar, but populations are principally in the drier, western parts of the island. Material in the CAS collection comes mainly from gallery forest, where individual workers have been taken in malaise traps and by beating. One small series has also been collected from an above ground rot pocket in a tree.