Gryllus rubens Scudder

Weissman, David B. & Gray, David A., 2019, Crickets of the genus Gryllus in the United States (Orthoptera: Gryllidae: Gryllinae), Zootaxa 4705 (1), pp. 1-277 : 83-90

publication ID	https://doi.org/ 10.11646/zootaxa.4705.1.1
publication LSID	lsid:zoobank.org:pub:F534C43A-AB09-4CB3-9B08-FD5BDFD90298
persistent identifier	https://treatment.plazi.org/id/182387A8-0933-FFCB-51F6-FC070013FE49
treatment provided by	Plazi
scientific name	Gryllus rubens Scudder
status

Treatment

Southeastern Field Cricket

Figs 71–82 View FIGURE 71 View FIGURE 72 View FIGURE 73 View FIGURE 74 View FIGURE 75 View FIGURE 76 View FIGURE 77 View FIGURE 78 View FIGURE 79 View FIGURE 80 View FIGURE 81 View FIGURE 82 , 85 View FIGURE 85 , 86 View FIGURE 86 , 90 View FIGURE 90 , Table 1 View TABLE 1

1902 Gryllus rubens Scudder. Psyche 9: p. 295. Holotype female, Auburn, Alabama. Type in ANSP, photos ( Fig. 74 View FIGURE 74 ) courtesy of J.D. Weintraub, ANSP. Plotting Scudder’s female holotype measurements of pronotal width of 6 mm and ovipositor length of 16 mm ( Scudder 1902) falls within G. rubens measurement cluster ( Fig. 75 View FIGURE 75 ).

1957 Acheta rubens (Scudder) . Alexander, 1957. p. 586.

1964 Gryllus rubens Scudder. Randell 1964 .

Distribution. One ( Fig. 71, R13-220 View FIGURE 71 View FIGURE 13 View FIGURE 14 View FIGURE 15 View FIGURE 16 View FIGURE 17 View FIGURE 18 View FIGURE 19 View FIGURE 20 View FIGURE 21 View FIGURE 22 View FIGURE 23 View FIGURE 24 View FIGURE 25 View FIGURE 26 View FIGURE 27 View FIGURE 28 View FIGURE 29 View FIGURE 30 View FIGURE 31 View FIGURE 32 View FIGURE 33 View FIGURE 34 View FIGURE 35 View FIGURE 36 View FIGURE 37 View FIGURE 38 View FIGURE 39 View FIGURE 40 View FIGURE 41 View FIGURE 42 View FIGURE 43 View FIGURE 44 View FIGURE 45 View FIGURE 46 View FIGURE 47 View FIGURE 48 View FIGURE 49 View FIGURE 50 View FIGURE 51 View FIGURE View FIGURE 53 View FIGURE 54 View FIGURE 55 View FIGURE 56 View FIGURE 57 View FIGURE 58 View FIGURE 59 View FIGURE 60 View FIGURE 61 View FIGURE 62 View FIGURE 63 View FIGURE 64 View FIGURE 65 View FIGURE 66 View FIGURE 67 View FIGURE 68 View FIGURE 69 View FIGURE 70 View FIGURE 72 View FIGURE 73 View FIGURE 74 View FIGURE 75 View FIGURE 76 View FIGURE 77 View FIGURE 78 View FIGURE 79 View FIGURE 80 View FIGURE 81 View FIGURE 82 View FIGURE 83 View FIGURE 84 View FIGURE 85 View FIGURE 86 View FIGURE 87 View FIGURE 88 View FIGURE 89 View FIGURE 90 View FIGURE 91 View FIGURE 92 View FIGURE 93 View FIGURE 94 View FIGURE 95 View FIGURE 96 View FIGURE 97 View FIGURE 98 View FIGURE 99 View FIGURE 100 View FIGURE 101 View FIGURE 102 View FIGURE 103 View FIGURE 104 View FIGURE 105 View FIGURE 106 View FIGURE 107 View FIGURE 108 View FIGURE 109 View FIGURE 110 View FIGURE 111 View FIGURE 112 View FIGURE 113 View FIGURE 114 View FIGURE 115 View FIGURE 116 View FIGURE 117 View FIGURE 118 View FIGURE 119 View FIGURE 120 View FIGURE 121 View FIGURE 122 View FIGURE 123 View FIGURE 124 View FIGURE 125 View FIGURE 126 View FIGURE 127 View FIGURE 128 View FIGURE 129 View FIGURE 130 View FIGURE 131 View FIGURE 132 View FIGURE 133 View FIGURE 134 View FIGURE 135 View FIGURE 136 View FIGURE 137 View FIGURE 138 View FIGURE 139 View FIGURE 140 View FIGURE 141 View FIGURE 142 View FIGURE 143 View FIGURE 144 View FIGURE 145 View FIGURE 146 View FIGURE 147 View FIGURE 148 View FIGURE 149 View FIGURE 150 View FIGURE 151 View FIGURE 152 View FIGURE 153 View FIGURE 154 View FIGURE 155 View FIGURE 156 View FIGURE 157 View FIGURE 158 View FIGURE 159 View FIGURE 160 View FIGURE 161 View FIGURE 162 View FIGURE 163 View FIGURE 164 View FIGURE 165 View FIGURE 166 View FIGURE 167 View FIGURE 168 View FIGURE 169 View FIGURE 170 View FIGURE 171 View FIGURE 172 View FIGURE 173 View FIGURE 174 View FIGURE 175 View FIGURE 176 View FIGURE 177 View FIGURE 178 View FIGURE 179 View FIGURE 180 View FIGURE 181 View FIGURE 182 View FIGURE 183 View FIGURE 184 View FIGURE 185 View FIGURE 186 View FIGURE 187 View FIGURE 188 View FIGURE 189 View FIGURE 190 View FIGURE 191 View FIGURE 192 View FIGURE 193 View FIGURE 194 View FIGURE 195 View FIGURE 196 View FIGURE 197 View FIGURE 198 View FIGURE 199 View FIGURE 200 View FIGURE 201 View FIGURE 202 View FIGURE 203 View FIGURE 204 View FIGURE 205 View FIGURE 206 View FIGURE 207 View FIGURE 208 View FIGURE 209 View FIGURE 210 View FIGURE 211 View FIGURE 212 View FIGURE 213 View FIGURE 214 View FIGURE 215 View FIGURE 216 View FIGURE 217 View FIGURE 218 View FIGURE 219 View FIGURE 220 ) of only two trilling US Gryllus found between 99° longitude (central Texas) and the Atlantic coast. See Walker (2019) and Gray (2011) for additional eastern localities.

Recognition characters and song. Medium sized, short or long hind winged crickets with an average PR of ~55 at 25°. Distinguished from morphologically similar and trilling, sometimes sympatric, G. texensis in that the latter has an average PR of ~80 at 25° ( Figs 71 View FIGURE 71 , 84 View FIGURE 84 ), more teeth in the file ( Figs 78 View FIGURE 78 , 79 View FIGURE 79 ), a shorter ovipositor ( Gray et al. 2001), and frequently, but not always, shorter bursts of pulses. Pulse rate at a given temperature faster, but with greater separation from G. texensis , in the late summer/fall generation than in the spring generation ( Walker 1998).

Along coastal Texas, in 2013, we found no overlap in dominant frequency, in many males, which was <5000 Hz in G. rubens but>5000 HZ in G. texensis . Yet around Tulsa , Oklahoma (S13-68), there is overlap and we wonder if this might reflect hybridization, environmental effects during development, or both. Additionally, Blankers (pers. comm.) stated that dominant frequency values that he used in Blankers et al. (2015) had a range of 4.18–5.88 KHz in G. rubens and 4.66–5.56 KHz in G. texensis . Unfortunately, these measured males were all from laboratory generations with unknown effects on the song.

Derivation of name. “rubens” apparently for the general reddish and rufo-testaceous markings on Scudder’s unique, long tegmina female specimen.

Geographic range. ( Fig. 76 View FIGURE 76 .) Most of our collection localities are near the western and northwestern boundaries of G. rubens’ distribution. See Gray (2011) and Walker (2019) for more complete eastern US distribution maps. Our most western locality is Bastrop State Park (S91-23), Texas, where G. rubens occurred with G. texensis . There we collected one male G. rubens (R91-39) with a PR of 53 at 25°C and with 100 file teeth and three G. texensis (R91-5, 6, 7) with PRs from 80–100 at 25°C and with 110–121 file teeth. We could not distinguish these two songs in the field.

Habitat. Lawns, pastures, and grassy roadsides. Life cycle and seasonal occurrence. No egg diapause. Two generations/year even at the northern extremes of its range ( Capinera et al. 2004). Adult peak abundances in spring and fall, representing the separate generations. Continuous generations in Florida ( Vélez & Brockmann 2006). Can be locally common.

Variation. Hind wing length: Populations variable for short and long hind winged individuals of both sexes ( Veazey et al. 1976, Walker 1987). Color: Within a population (e.g. S02-58, Missouri), individuals ( Fig. 80 View FIGURE 80 ) may have black hind femurs and tegmina compared to more typical brown/reddish ones. Pronotum: Usually very shiny in males, possibly less so in females. Song: Usually an evenly spaced trill but one male from Missouri, with 95 file teeth, ( Fig. 81 View FIGURE 81 , R02-74, S02-58) with variable grouping of pulses.

Specimens examined. (Total: 54♂ 27♀). Arkansas: Garland Co., Jessieville, 19-vi-1993, 750’ (S93-46) 1♂. Yell Co., Dardonelle , 19-vi-1993, 400’ (S93-48) 2♂ . Florida : Alachua Co., Gainesville , 2-x-1986 (S86-128), TJ Walker, 20♂ 7♀ . Indiana : Warrick Co., 4 m S Dale 4-vi-2003, 650’, 38° 7.228’ -87° 1.591’ (S03-61) 1♂ . Maryland : Prince George Co., College Park, 30-v-2004, 500’ (S04-35) 2♂ . Missouri : Cape Girardeau Co., Millersville, 9-viii-2002, 320’ (S02-58) 6♂ 9♀ ; Iron Co., Pilot Knob , 9-viii-2002, 840’ (S02-57) 2♂ 1♀. Oklahoma : Texas Co., Guymon, 1-vii-2009, 3380’ (S09-77) 1♂ . Tulsa Co., Lake Keystone Dam area, 22-v-2001, 650’, 36° 9.092’ -96° 15.043’ (S01-47) 1♂; Tulsa , 15-vii-2013, 775’ (S13-67, 68) 9♂. Texas : Bastrop Co., Bastrop State Park, 31-v-1991, 700’ (S91-23) 1♂ . Galveston Co., High Island , 10-vi-2011, 5’ (S11-28) 4♀ . Harris Co., Cypress , 148’, 13-vii-2013 (S13-64) 3♂ . Jefferson Co., Sabine Pass , 10-vi-2011, 20’ (S11-31) 3♂ 5♀ ; Sea Rim State Park , 10-vi-2011, 5’ (S11- 29) 1♀ ; Marion Co., Caddo Lake State Park , 18-vi-1993, 300’ (S93-42) 1♂ . Orange Co., Beaumont , 1-vi-1991, 50’ (S91-32) 1♂ .

DNA. Multilocus d437 from Florida, Jackson Co., Marianna, 28-ix-1999, 117’, 30.774°, -85.227°, pulse rate in this male 53 at 25°C. Closest relatives (Gray et al. 2019): G. texensis (see Gray 2006; Gray et al. 2006) and G. regularis . See also Blankers et al. (2018), which compared transcriptomic genetic variation in G. rubens and G. texensis . In that study, several loci were fixed for genetic differences between G. rubens and G. texensis , so in principle there are diagnostic genetic differences between these taxa, but they are not applicable in any practical sense.

Discussion. When standing near simultaneously trilling males of G. rubens and G. texensis , one can sometimes hear subtle differences between the two songs, probably reflective of the different pulse rates and dominant frequencies. Currently, there is no single, definitive morphological character that separates male G. rubens from male G. texensis ( Walker 1998, Gray et al. 2006), although we do present new data ( Fig. 79 View FIGURE 79 ) showing promise when comparing number of file teeth vs. teeth/mm. In the past, positive male identification has been exclusively linked to differences in song PR. Unfortunately, the ability of this one song parameter to separate the two species gets murky in some populations. Gray & Cade (2000a) demonstrated an increase in PR in G. rubens of ~3 for each 1°C rise in temperature and an increase in PR in G. texensis of ~5 for each 1°C rise. Martin et al. (2000) demonstrated an increase in PR of 3.5 for every 1°C increase in recording temperature in G. texensis (called “ G. integer ” by Martin et al. 2000). We applied a modification of this temperature correction (+4 pulses for each 1°C difference from 25°C because we did not want to prejudge which species that we decided that we were recording) to 16 males from Tulsa , OK (S13-68) recorded in the laboratory between 22–28°C and whose PR we normalized to 25°C: we find no unambiguous separation at this locality and get only a modestly bimodal PR ( Fig. 82 View FIGURE 82 ).

While we did not find this ambiguity, in pulse rate, to be geographically widespread, it is also not unique: For instance, Walker (1998, p. 175) notes:

“…songs I attributed to G. rubens had a slightly higher average pulse rate in the zone of overlap [with G. texensis between western Florida and eastern Texas] than farther east and both species varied more in pulse rate between individuals from the same site and for the same individual from time to time than in the many other cricket species

I had studied. G. rubens and texensis [called ‘ G. integer ’ by Walker in 1998] were not as clearly separated by their songs as other sympatric pairs of sibling species of crickets.”

Instead of finding character displacement where they overlap, Walker (1998) found the opposite and concluded that the two species may hybridize in areas of overlap in western Florida. Such hybridization is achievable in the laboratory ( Smith & Cade 1987), but, based on song phenotype, appears to be rare in sympatry ( Izzo & Gray 2004). Nonetheless, we wonder if they may be hybridizing at our Tulsa , OK, site (S13-68), as discussed above. Using transcriptomic data, Blankers et al. (2018) found no evidence of interspecific gene flow more recently than ca. ~18K years, but, it must be noted, the source populations for that study were from allopatry. Additionally, Walker (1998) documented that different generations have different pulse rates, now further investigated by Beckers et al. (2019), so variable environmental effects are certainly possible.

G. rubens has been used in hybridization studies ( Smith & Cade 1987; Cade & Tyshenko 1990), tachinid fly parasitism ( Vélez & Brockmann 2006), effect of temperature on pulse rates ( Doherty & Callos 1991; Walker 2000), female phonotaxis ( Doherty & Callos 1991), song character displacement ( Walker 1998; Izzo & Gray 2004), courtship song divergence ( Fitzpatrick & Gray 2001) and impact on potential for hybridization ( Gray 2004), peripatric speciation ( Gray et al. 2008, Blankers et al. 2018), genetics of speciation ( Blankers et al. 2019), aggressiveness related to habitat ( Jang et al. 2008), and male response to conspecific song ( Jang 2011). Past research is summarized in Gray (2011).