Vibrational Communication of Scolypopa australis (Walker, 1851) (Hemiptera: Ricaniidae)—Towards a Novel Sustainable Pest Management Tool

A study was undertaken to determine whether Scolypopa australis, the passionvine hopper, communicates using substrate-borne vibrations, as its use of such signals for communication is currently unknown. This insect is a costly pest to the kiwifruit industry in New Zealand, where few pest management tools can be used during the growing season. Vibrations emitted by virgin females and males of S. australis released alone on leaves of Griselinia littoralis were recorded with a laser vibrometer to identify and characterise potential spontaneous calling signals produced by either sex. In addition to single-insect trials, preliminary tests were conducted with female–male pair trials to determine whether individuals exchanged signals. The signal repertoire of S. australis includes a male calling signal and two female calling signals. However, no evidence of duetting behaviour that is potentially necessary for pair formation has been found to date. Our outcome suggests that a deeper understanding of the role of vibrational communication employed by S. australis is needed, and by disclosing the pair formation process, a new residue-free pest management tool against this pest may be developed. In addition, this vibration-based tool could contribute to future biosecurity preparedness and response initiatives.

Review of the genus Taurotettix Haupt, 1929 (Homoptera: Cicadellidae: Deltocephalinae: Cicadulini): morphology, acoustic signals, and geographical variability

The leafhopper genus Taurotettix includes two subgenera, Taurotettix (Taurotettix) and Taurotettix (Callistrophia), and three species, T. (T.) beckeri (Fieber, 1885), T. (C.) modesta (Mityaev, 1971), and T. (C.) elegans (Melichar, 1900). T. (C.) elegans is subdivided into two subspecies, T. (C.) elegans elegans and T. (C.) elegans subornata (Mityaev, 1971) stat. nov. Illustrated descriptions and data on biology and distribution for all taxa are given. Oscillograms of male calling signals of T. (T.) beckeri, T. (C.) modesta, and T. (C.) elegans elegans are provided. A hypothesis about speciation in Taurotettix (Callistrophia) is presented.

Review of the Neoaliturus fenestratus (Herrich-Schäffer, 1834) species group (Homoptera: Auchenorrhyncha: Cicadellidae: Deltocephalinae: Opsiini) from Russia, Kazakhstan, and Central Asia

In Russia, Kazakhstan, and Central Asia the Neoaliturus fenestratus species group includes eight species. Illustrated descriptions, oscillograms of male calling signals, and data on host plants and distribution for all species are given. One new species from European Russia and two new species from Kazakhstan and Central Asia are described, and the synonymy N. fenestratus (Herrich-Schäffer, 1834) = N. lituratus Dubovskiy, 1966, syn. n. is established. Considerations concerning possible modes of diversification of species of this group are provided.

Auditory Virtual Reality for Insect Phonotaxis

Insects have a sophisticated ability to navigate real environments. Virtual reality (VR) is a powerful tool for analyzing animal navigation in laboratory studies and is the most successful when used in the study of visually guided behaviors. However, the use of VR with non-visual sensory information, such as sound, on which nocturnal insects rely, for analyzing animal navigation has not been fully studied. We developed an auditory VR for the study of auditory navigation in crickets, Gryllus bimaculatus. The system consisted of a spherical treadmill on which a tethered female cricket walked. Sixteen speakers were placed around the cricket for auditory stimuli. The two optical mice attached to the treadmill measured the cricket’s locomotion, and the sound pressure and direction of the auditory stimuli were controlled at 100 Hz based on the position and heading of the cricket relative to a sound source in a virtual arena. We demonstrated that tethered female crickets selectively responded to the conspecific male calling song and localized the sound source in a virtual arena, which was similar to the behavior of freely walking crickets. Further combinations of our system with neurophysiological techniques will help understand the neural mechanisms for insect auditory navigation.

Neoxabea mexicana sp. nov. (Gryllidae: Oecanthinae): A new species from Mexico and a key for Neoxabea in North and Central America

A new species of tree cricket, Neoxabea mexicanasp. nov., is described from northeast Mexico. Although it has morphological similarities to two other species found in Mexico, there are distinguishing characters, such as a well-developed tubercle on the pedicel, black markings on the maxillary palpi, one of the two pairs of spots on the female wings positioned at the base of the wings, stridulatory teeth count, and the pulse rate of the male calling song. The calling song description and pre-singing stuttering frequencies are provided. Character comparisons that rule out other species in the genus are presented. The common name given to this new species is Mexican tree cricket. Sound recordings and video are available online. We also make some clarification of the status of Neoxabea formosa (Walker, 1869), described as Oecanthus formosus, and present a key of Neoxabea in North and Central America.

Does the choosiness of female crickets change as they age?

For crickets, which approach singing males by phonotaxis, the female choosiness hypothesis postulates that young females should be more selective of male calling song patterns than older individuals. However, there is no information about the behavioural preferences of females over their complete adulthood. We analysed phonotaxis in female Gryllus bimaculatus throughout their entire adult lifetime and measured the impact of sound amplitude, carrier frequency, and the temporal pattern of test songs on their auditory response. Females of all ages demonstrated their best responses to male calling songs with a pulse period of 34-42 ms, a carrier frequency of 4.5 kHz and a sound pressure level of 75dB SPL. The response profile to somewhat less optimal song types did vary with age, but not in a manner consistent with a simple loosening of selectiveness in older females. Age however had an effect on the overall strength of phonotaxis, as very old females showed an overall diminishing response to all song types. Our data suggest that although there are minor changes in the relative preferences of crickets to individual song elements as they age, the breadth of song patterns that they will perform phonotaxis to remains similar across age groups.

Pycnogaster ribesiglesiasii, a new species of Ephippigerini (Orthoptera: Tettigoniidae: Bradyporinae) from Catalonia (northeast of the Iberian Peninsula)

A new species of the genus Pycnogaster Graells, 1851 is described from Catalonia (Northeast of the Iberian Peninsula). Pycnogaster ribesiglesiasii n. sp. was collected in the Plana d’Ancosa in a calcicolous stepic scrub dominated mainly by thyme (Thymus vulgaris). L. ribesiglesiasii is compared to P. sanchezgomezi Bolívar, 1897 from which it can be separated mainly by the shape of the male cerci, the titillators and the male calling song. In addition, in the females by the protuberance of the seventh (7th) sclerite and the shape of subgenital plate.

Sex differences in response to environmental and social breeding cues in an amphibian

The relative influence of climatic and social factors on sex-specific variation in reproductive behaviour remains poorly understood. Here, we examine the influence of multiple climatic cues in combination with a social cue on the reproductive behaviours of males and females in a terrestrial breeding toadlet (Pseudophryne coriacea). Over a 115-day breeding season, arrival patterns of each sex, and male calling activity, were recorded daily, while climatic variables were logged continuously. Multivariate analysis showed that arrival of males at the breeding site, as well as male nightly calling activity, were most strongly influenced by a climatic variable (rainfall). By contrast, female arrival was strongly correlated with a social variable (male calling activity), with abiotic conditions having no influence, other than a moderate influence of lunar phase (lunar illumination). These results suggest that cues used for breeding are sex specific and provide new evidence that combinations of climatic and social cues can be integrated into breeding decisions.