DOI: 10.5061/dryad.866t1g20s
title: Data from: Interspecific competition leads to more long-winged morphs in two sympatric cricket species

description: Coexistence mechanisms for species competing for the same resource include
 resource partitioning, neutrality, microhabitat preference, and trade-offs
 between competitive and dispersal abilities. We explored the coexistence
 mechanism of two species of trigonidiid crickets (Dianemobius
 nigrofasciatus and Polionemobius taprobanensis) that share the same
 habitat. Dianemobius nigrofasciatus is more common in areas where the
 ground surface is somewhat open, while P. taprobanensis is more common in
 more densely vegetated environments. The effects of micro-environmental
 differences, similarities in competitive ability, and investment in
 dispersal ability under interspecific competitive conditions on the
 coexistence of these species were examined using laboratory experiments.
 Both P. taprobanensis and D. nigrofasciatus performed better in vegetated
 environments. Although the adult emergence of D. nigrofasciatus was
 delayed by the presence of P. taprobanensis, the emergence rate of P.
 taprobanensis was not significantly affected by D. nigrofasciatus. The
 presence of P. taprobanensis caused a higher frequency of a long-winged
 morph (macropterous) of D. nigrofasciatus. The results suggest that D.
 nigrofasciatus is inferior to P. taprobanensis in interspecific
 competition, and it, therefore, disperses (as macropterous adults) at
 greater rates in the presence of P. taprobanensis. Furthermore, it may be
 that D. nigrofasciatus has been forced to change its preferred
 microhabitat from vegetative habitats, which are inherently more suitable,
 to more open environments due to competition. The above mechanisms are
 thought to allow the two species to coexist in the same habitat.
description: We explored the coexistence mechanism of two species of
 trigonidiid crickets (Dianemobius nigrofasciatus and Polionemobius
 taprobanensis) that share the same habitat. Dianemobius nigrofasciatus is
 more common in areas where the ground surface is somewhat open, while P.
 taprobanensis is more common in more densely vegetated environments. The
 effects of micro-environmental differences, similarities in competitive
 ability, and investment in dispersal ability under interspecific
 competitive conditions on the coexistence of these species were examined
 using laboratory experiments. To determine whether the
 density of heterospeciﬁc crickets affected survival or adult emergence
 rates during the nymphal stage, a laboratory experiment was carried out in
 plastic containers (height = 10 cm, diameter = 10cm). Newly emerged first
 instar nymphs were collected within 72 hours. Estimated population density
 in the field was 3-4 individuals/m2 (see supplemental materials), but this
 is the density of adults or final instar nymphs. The density of nymphs
 immediately after hatching is probably higher (one female of this species
 lays about 80 eggs). On the other hands, these crickets can grow and
 reproduce at fairly high densities. In previous studies, D. nigrofasciatus
 reared at 5.2 to 150 nymphs / L (Shimizu & Goto, 2024, Masaki
 1972); P. taprobanensis can also be reared at 100 nymphs / L at
 high-density case (Tanaka 2022). To examine the effects of interspecific
 competition in this study, the experiment was conducted at densities that
 are assumed to be higher than in the field (i.e., 38.2 nymph / L).
 Treatments (numbers of crickets of each species) were as follows (no. of
 D. nigrofasciatus: no. of P. taprobanensis): (30:0), (0:30), and (15:15).
 These three treatments were crossed with two types of rearing conditions:
 (1) the open habitat treatment consisted of wet soil and a portion of one
 paper egg carton (portion for one egg) and (2) the vegetated treatment
 consisted of wet soil from which Japanese lawn grass (Zoysia japonica)
 turf grew on the whole surface (Fig. 2b,c). The lawn grass turf was
 collected in a sports ground at Kagoshima University. There were seven
 replicates for each combination of the three densities and the two rearing
 conditions. The containers were maintained in incubators (CDB-14LA, Daiwa
 Industry LTD., Osaka, Japan) at 27°C and a short-day photoperiod (12L:12D
 photoperiod). Under the temperature and photoperiod, half of the first
 instar nymphs become adults within 40 days (Masaki, 1972). The positions
 of all containers were rotated in the incubators every 3 or 5 days to
 homogenize the environmental conditions. The food was presented in two
 containers (1.4 cm diameter), not directly on the soil, to prevent mold.
 The two types of food (cat chow and guinea pig food) were powdered and
 mixed. Because of the small size of the food containers, it was not
 possible for more than one individual over 3-4 instar nymphs to feed at
 the same time. The food was changed every three days.
 Nymphs were reared for 38 days after the start of the experiment,
 and the number of surviving crickets (survival rate) and their life stage
 (i.e., adults or nymphs) by species and sex (adult emergence rate) were
 recorded. The wing morph (micropterous or macropterous) of all adults was
 also recorded. The macropterous morph is easily determined by the hind
 wings being longer than the end of the body. Tibial lengths (both tibia
 for each individual) of adults were measured using a digital microscope
 (3R-MSUSB401; 3R Solution Corp., Tokyo, Japan) as an index of body size.
 Head width is usually used as an indicator of body size in these crickets
 (e.g., Matsuda et al. 2018; 2019). However, in this experiment, the entire
 container was frozen in order to stop the developmental stage at the end
 of the experiment. The heads of frozen individuals are often twisted and
 complex to measure accurately. Therefore, we used the tibial length, which
 is easy to measure accurately even in frozen individuals, as an indicator
 of body size.
description: # Data from: Interspecific competition leads to more long-winged morphs in
 two sympatric cricket species
 [https://doi.org/10.5061/dryad.866t1g20s](https://doi.org/10.5061/dryad.866t1g20s) ## Description of the data and file structure This study examined how two cricket species, *Dianemobius nigrofasciatus* and *Polionemobius taprobanensis*, coexist in shared habitats with differing vegetation density. Laboratory experiments tested the effects of microhabitat, interspecific competition, and dispersal traits on survival and development. Nymphs were reared under controlled conditions across different densities and habitat treatments. Survival rates, adult emergence, wing morph, and tibial length were measured to assess competitive dynamics and body size. ### Files and variables #### File: size.txt **Description: size**  ##### Variables * s: P. taprobanensis * m: D. nigrofasciatus * density_D: initial number of  D. nigrofasciatus per container * densityh_P: initial number of P. taprobanensis per container * size: mean tibia length of right and left (mm) * sex m: male, f: female * otherspecific 1: presence, 0: absence * environment 1: vegitative habitat, 0: open habitat #### File: lifehistory.txt **Description**: life history ##### Variables * density_D: initial number of  D. nigrofasciatus per container * densityh_P:initial number of P. taprobanensis per container * otherspecific 1: presence, 0: absence * environment 1: vegitative habitat, 0: open habitat * long: number of macropterous individuals per container * short: number of micropterous individuals per container