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Groot AT, Blankers T, Halfwerk W, Burdfield Steel E. The Evolutionary Importance of Intraspecific Variation in Sexual Communication Across Sensory Modalities. ANNUAL REVIEW OF ENTOMOLOGY 2024; 69:21-40. [PMID: 37562048 DOI: 10.1146/annurev-ento-030223-111608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The evolution of sexual communication is critically important in the diversity of arthropods, which are declining at a fast pace worldwide. Their environments are rapidly changing, with increasing chemical, acoustic, and light pollution. To predict how arthropod species will respond to changing climates, habitats, and communities, we need to understand how sexual communication systems can evolve. In the past decades, intraspecific variation in sexual signals and responses across different modalities has been identified, but never in a comparative way. In this review, we identify and compare the level and extent of intraspecific variation in sexual signals and responses across three different modalities, chemical, acoustic, and visual, focusing mostly on insects. By comparing causes and possible consequences of intraspecific variation in sexual communication among these modalities, we identify shared and unique patterns, as well as knowledge needed to predict the evolution of sexual communication systems in arthropods in a changing world.
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Affiliation(s)
- Astrid T Groot
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Netherlands; , ,
| | - Thomas Blankers
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Netherlands; , ,
| | - Wouter Halfwerk
- Amsterdam Institute for Life and Environment (A-LIFE), VU Amsterdam, Netherlands;
| | - Emily Burdfield Steel
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Netherlands; , ,
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2
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Rebrina F, Petróczki K, Inhofer M, Reinhold K, Schmoll T. Motorway age is linked to larger body size, but not song carrier frequency, in male grasshoppers from roadside populations. Evol Ecol 2020. [DOI: 10.1007/s10682-020-10077-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Aufderheide J, Ronacher B. The impact of age and egg-laying cycle on female grasshoppers' preference functions for acoustic signals. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 205:103-111. [PMID: 30506392 DOI: 10.1007/s00359-018-1307-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 10/27/2022]
Abstract
Female responsiveness and the shape of preference functions for male signal traits are important determinants for male mating success. We observed the responsiveness and the selectivity of virgin grasshopper females (Chorthippus biguttulus L.) for different features of males' acoustic signals throughout their life span to detect possible influences of age on the females' preference functions. In particular, we explored the hypothesis that the females may become less selective with increasing age and, therefore, would start to accept songs that are normally rejected. Such an age effect could relieve the selection pressure on male signal traits. In the majority of animals tested, the general responsiveness decreased with age although a few individuals exhibited an opposite trend. Contrary to the above expectation, there was no indication of a loss of selectivity in older females or an increased acceptance of normally unattractive song models. The timing within the oviposition cycle had a strong effect on responsiveness: near oviposition the general responsiveness increased and with it also the half width of the preference functions. However, highly unattractive song models remained unattractive also near oviposition.
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Affiliation(s)
- Jennifer Aufderheide
- Behavioural Physiology Group, Department of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Bernhard Ronacher
- Behavioural Physiology Group, Department of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany.
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Valverde JP, Eggert H, Kurtz J, Schielzeth H. Condition-dependence and sexual ornamentation: Effects of immune challenges on a highly sexually dimorphic grasshopper. INSECT SCIENCE 2018; 25:617-630. [PMID: 28229542 DOI: 10.1111/1744-7917.12448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/16/2016] [Accepted: 01/03/2017] [Indexed: 05/24/2023]
Abstract
Sexual ornaments contribute substantially to phenotypic diversity and it is particularly relevant to understand their evolution. Ornaments can assume the function of signals-of-quality that the choosy sex uses to evaluate potential mating partners. Often there are no obvious direct benefits and investment into mate choice is primarily rewarded by beneficial alleles that are inherited to the offspring. Inter-sexual communication via sexual ornaments requires honesty of the sexual signal, yet the question of what maintains honesty remains only partially solved. One solution is that honesty is maintained by trait expression being dependent on individual condition, since condition-dependent trait expression offers an effectively inexhaustible source of genetic variability. Here we test in the highly sexually dimorphic club-legged grasshopper Gomphocerus sibiricus if putative sexual ornaments, in particular the striking front-leg clubs, are more strongly affected by a lipopolysaccharide (LPS) immune challenge than putatively not sexually selected traits. Our results show overall little condition-dependent expression of morphological and song traits, with sexually selected traits exhibiting effects comparable to nonsexually selected traits (with the possible exception of stridulatory file length and syllable-to-pause ratio in advertisement songs). Interestingly, field observations of individuals of lethally parasitized individuals suggest that a very strong environmental challenge can specifically affect the expression of the front-leg clubs. The presence of 1% of males in natural populations with missing or heavily deformed clubs plus 5% with minor club deformations furthermore indicate that there are risks associated with club development during final ecdysis and this might act as a filter against deleterious alleles.
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Affiliation(s)
- J Pablo Valverde
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Hendrik Eggert
- Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Holger Schielzeth
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
- Department of Population Ecology, Institute of Ecology, Friedrich Schiller University, Jena, Germany
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5
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The ‘hot male’ hypothesis: do female crickets prefer males with increased body temperature in mate choice scenarios? Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Robustness of an innate releasing mechanism against degradation of acoustic communication signals in the grasshopper Chorthippus biguttulus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:319-328. [PMID: 29294159 DOI: 10.1007/s00359-017-1243-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
Abstract
Noise is a challenge for animals that use acoustic communication to find a mate. A potent source of noise in animal communication is that arising from other conspecific signals, whose co-occurrence can result in extensive interference-evident as the so called "cocktail-party problem"-that may affect the receiver mechanisms to detect potential mates. We studied grasshopper females to explore how modifications of the song pattern influence song recognition. First, we degraded an attractive model song with random fluctuations of increasing amplitudes out of different frequency bands, and determined "critical degradation levels" at which the females ceased to respond. A masker band with frequencies between 0 and 200 Hz, which covers the frequency range of the natural song envelope, was by 3-5 dB more destructive in hampering signal recognition than frequencies above 200 Hz. As second approach, we applied temporal disturbances such as accentuations or gaps at different positions within the song subunits and observed how response behavior was affected. Accentuations at subunit start increased, whereas those in the midst or at the end of a subunit reduced attractiveness. Gaps at these positions had diverse effects. The results are discussed with respect to neuronal filtering.
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Köhler G, Samietz J, Schielzeth H. Morphological and colour morph clines along an altitudinal gradient in the meadow grasshopper Pseudochorthippus parallelus. PLoS One 2017; 12:e0189815. [PMID: 29284051 PMCID: PMC5746220 DOI: 10.1371/journal.pone.0189815] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 12/02/2017] [Indexed: 11/19/2022] Open
Abstract
Many animals show altitudinal clines in size, shape and body colour. Increases in body size and reduction in the length of body appendices in colder habitats are usually attributed to improved heat conservation at lower surface-to-volume ratios (known as Bergmann’s and Allen’s rule, respectively). However, the patterns are more variable and sometimes reversed in small ectotherms that are affected by shortened growing seasons. Altitude can also affect colouration. The thermal melanism hypothesis predicts darker colours under cooler conditions because of a thermoregulatory advantage. Darker colours may also be favoured at high altitudes for reasons of UV protection or habitat-dependent crypsis. We studied altitudinal variation in morphology and colour in the colour-polymorphic meadow grasshopper Pseudochorthippus parallelus based on 563 individuals from 17 populations sampled between 450 and 2,500 m asl. Pronotum length did not change with altitude, while postfemur length decreased significantly in both sexes. Tegmen (forewing) length decreased in males, but not in females. The results indicate that while body size, as best quantified by pronotum length, was remarkably constant, extended appendices were reduced at high altitudes. The pattern thus follows Allen’s rule, but neither Bergmann’s nor converse Bergmann’s rule. These results indicate that inference of converse Bergmann’s rule based on measurements from appendices should be treated with some caution. Colour morph ratios showed significant changes in both sexes from lowland populations dominated by green individuals to high-altitude populations dominated by brown ones. The increase of brown morphs was particularly steep between 1,500 and 2,000 m asl. The results suggest shared control of colour in males and females and local adaptation along the altitudinal gradient following the predictions of the thermal melanism hypothesis. Interestingly, both patterns, the reduction of body appendices and the higher frequency of brown individuals, may be explained by a need for efficient thermoregulation under high-altitude conditions.
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Affiliation(s)
- Günter Köhler
- Population Ecology Group, Institute of Ecology, Friedrich Schiller University, Jena, Germany
| | - Jörg Samietz
- Population Ecology Group, Institute of Ecology, Friedrich Schiller University, Jena, Germany
| | - Holger Schielzeth
- Population Ecology Group, Institute of Ecology, Friedrich Schiller University, Jena, Germany
- * E-mail:
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Clemens J, Aufderheide J, Ronacher B. Relative weighting of acoustic information during mating decisions in grasshoppers indicates signatures of sexual selection. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:891-901. [PMID: 28733816 PMCID: PMC5644699 DOI: 10.1007/s00359-017-1200-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 06/12/2017] [Accepted: 07/10/2017] [Indexed: 11/29/2022]
Abstract
The decision with whom to mate is crucial in determining an individual's fitness and is often based on the evaluation of visual or acoustic displays produced during courtship. Accordingly, the algorithms for evaluating such courtship signals are shaped by sexual selection and should reflect the expected benefits and costs of mating: signals bearing heterospecific features should be rapidly rejected, since mating would produce no fertile offspring, while signals resembling conspecific ones should be weighted proportional to mate quality. We test these hypotheses in females of the grasshopper Chorthippus biguttulus who assess males by their song, which is produced as a sequence of subunits with species and individual specific signatures. We present mixed sequences of subunits with conflicting cues and use a computational model of decision-making to infer how sensory information is weighted and integrated over the song. Consistent with our hypothesis, females do weight sensory cues according to the expected fitness benefits/costs: heterospecific subunits are weighted particularly negatively and lead to a rejection of the male early in the song. Conspecific subunits are weighted moderately, permitting a more complete evaluation of the full song. However, there exists an overall negative bias against mating, possible causes of which are discussed.
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Affiliation(s)
- Jan Clemens
- Princeton Neuroscience Institute, Princeton University, Washington Road, Princeton, NJ, 08540, USA.
| | - Jennifer Aufderheide
- Behavioral Physiology Group, Department of Biology, Humboldt Universität zu Berlin, 10115, Berlin, Germany
| | - Bernhard Ronacher
- Behavioral Physiology Group, Department of Biology, Humboldt Universität zu Berlin, 10115, Berlin, Germany.
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García-Navas V, Noguerales V, Cordero PJ, Ortego J. Ecological drivers of body size evolution and sexual size dimorphism in short-horned grasshoppers (Orthoptera: Acrididae). J Evol Biol 2017; 30:1592-1608. [PMID: 28609564 DOI: 10.1111/jeb.13131] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/26/2017] [Accepted: 06/05/2017] [Indexed: 02/03/2023]
Abstract
Sexual size dimorphism (SSD) is widespread and variable in nature. Although female-biased SSD predominates among insects, the proximate ecological and evolutionary factors promoting this phenomenon remain largely unstudied. Here, we employ modern phylogenetic comparative methods on eight subfamilies of Iberian grasshoppers (85 species) to examine the validity of different models of evolution of body size and SSD and explore how they are shaped by a suite of ecological variables (habitat specialization, substrate use, altitude) and/or constrained by different evolutionary pressures (female fecundity, strength of sexual selection, length of the breeding season). Body size disparity primarily accumulated late in the history of the group and did not follow a Brownian motion pattern, indicating the existence of directional evolution for this trait. We found support for the converse of Rensch's rule (i.e. females are proportionally bigger than males in large species) across all taxa but not within the two most speciose subfamilies (Gomphocerinae and Oedipodinae), which showed an isometric pattern. Our results do not provide support for the fecundity or sexual selection hypotheses, and we did not find evidence for significant effects of habitat use. Contrary to that expected, we found that species with narrower reproductive window are less dimorphic in size than those that exhibit a longer breeding cycle, suggesting that male protandry cannot solely account for the evolution of female-biased SSD in Orthoptera. Our study highlights the need to consider alternatives to the classical evolutionary hypotheses when trying to explain why in certain insect groups males remain small.
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Affiliation(s)
- V García-Navas
- Department of Integrative Ecology, Estación Biológica de Doñana (EBD-CSIC), Seville, Spain
| | - V Noguerales
- Grupo de Investigación de la Biodiversidad Genética y Cultural, Instituto de Investigación en Recursos Cinegéticos IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - P J Cordero
- Grupo de Investigación de la Biodiversidad Genética y Cultural, Instituto de Investigación en Recursos Cinegéticos IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - J Ortego
- Department of Integrative Ecology, Estación Biológica de Doñana (EBD-CSIC), Seville, Spain
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Finck J, Kuntze J, Ronacher B. Chemical cues from females trigger male courtship behaviour in grasshoppers. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:337-45. [PMID: 27025933 DOI: 10.1007/s00359-016-1081-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/03/2016] [Accepted: 03/05/2016] [Indexed: 10/22/2022]
Abstract
Gomphocerine grasshoppers use species-specific calling songs for sex recognition and mate attraction. In two closely related species, Chorthippus biguttulus and C. mollis, acoustic communication is the only experimentally characterized communication channel that elicits male courtship behaviour. However, courtship in these species involves extensive close-range interactions that are likely to be mediated by other signalling modalities, in particular chemical cues. We developed a bioassay to determine if female cuticular hydrocarbons (CHCs) act as chemical cues that induce courtship behaviour, and if males assess variation in CHCs to determine whether or not to court a female. The results of this approach provide evidence that grasshopper males use species- and sex-specific information from CHC signals and respond with a courtship song to the CHC profile of conspecific females but not to the CHC profile of heterospecific females and conspecific males. We conclude that males of C. biguttulus and C. mollis use multimodal channels for mating decisions, based on both acoustic and olfactory cues. We discuss various factors that might favour the evolution of male choosiness in grasshoppers.
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Affiliation(s)
- Jonas Finck
- Behavioural Physiology, Department of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 43, 10115, Berlin, Germany. .,Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, 10115, Berlin, Germany.
| | - Janine Kuntze
- Behavioural Physiology, Department of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 43, 10115, Berlin, Germany
| | - Bernhard Ronacher
- Behavioural Physiology, Department of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 43, 10115, Berlin, Germany
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12
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Rojas B. Behavioural, ecological, and evolutionary aspects of diversity in frog colour patterns. Biol Rev Camb Philos Soc 2016; 92:1059-1080. [DOI: 10.1111/brv.12269] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 02/26/2016] [Accepted: 02/29/2016] [Indexed: 02/03/2023]
Affiliation(s)
- Bibiana Rojas
- Centre of Excellence in Biological Interactions, Department of Biology and Environmental Sciences; University of Jyvaskyla; PO Box 35 Jyväskylä FI 40001 Finland
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13
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Wirtssohn S, Ronacher B. Temporal integration at consecutive processing stages in the auditory pathway of the grasshopper. J Neurophysiol 2015; 113:2280-8. [PMID: 25609104 DOI: 10.1152/jn.00390.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 01/20/2015] [Indexed: 11/22/2022] Open
Abstract
Temporal integration in the auditory system of locusts was quantified by presenting single clicks and click pairs while performing intracellular recordings. Auditory neurons were studied at three processing stages, which form a feed-forward network in the metathoracic ganglion. Receptor neurons and most first-order interneurons ("local neurons") encode the signal envelope, while second-order interneurons ("ascending neurons") tend to extract more complex, behaviorally relevant sound features. In different neuron types of the auditory pathway we found three response types: no significant temporal integration (some ascending neurons), leaky energy integration (receptor neurons and some local neurons), and facilitatory processes (some local and ascending neurons). The receptor neurons integrated input over very short time windows (<2 ms). Temporal integration on longer time scales was found at subsequent processing stages, indicative of within-neuron computations and network activity. These different strategies, realized at separate processing stages and in parallel neuronal pathways within one processing stage, could enable the grasshopper's auditory system to evaluate longer time windows and thus to implement temporal filters, while at the same time maintaining a high temporal resolution.
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Affiliation(s)
- Sarah Wirtssohn
- Behavioural Physiology Group, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany; and Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Bernhard Ronacher
- Behavioural Physiology Group, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany; and Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
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Meckenhäuser G, Krämer S, Farkhooi F, Ronacher B, Nawrot MP. Neural representation of calling songs and their behavioral relevance in the grasshopper auditory system. Front Syst Neurosci 2014; 8:183. [PMID: 25565983 PMCID: PMC4271601 DOI: 10.3389/fnsys.2014.00183] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 09/09/2014] [Indexed: 11/30/2022] Open
Abstract
Acoustic communication plays a key role for mate attraction in grasshoppers. Males use songs to advertise themselves to females. Females evaluate the song pattern, a repetitive structure of sound syllables separated by short pauses, to recognize a conspecific male and as proxy to its fitness. In their natural habitat females often receive songs with degraded temporal structure. Perturbations may, for example, result from the overlap with other songs. We studied the response behavior of females to songs that show different signal degradations. A perturbation of an otherwise attractive song at later positions in the syllable diminished the behavioral response, whereas the same perturbation at the onset of a syllable did not affect song attractiveness. We applied naïve Bayes classifiers to the spike trains of identified neurons in the auditory pathway to explore how sensory evidence about the acoustic stimulus and its attractiveness is represented in the neuronal responses. We find that populations of three or more neurons were sufficient to reliably decode the acoustic stimulus and to predict its behavioral relevance from the single-trial integrated firing rate. A simple model of decision making simulates the female response behavior. It computes for each syllable the likelihood for the presence of an attractive song pattern as evidenced by the population firing rate. Integration across syllables allows the likelihood to reach a decision threshold and to elicit the behavioral response. The close match between model performance and animal behavior shows that a spike rate code is sufficient to enable song pattern recognition.
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Affiliation(s)
- Gundula Meckenhäuser
- Neuroinformatics and Theoretical Neuroscience, Department of Biology, Chemistry and Pharmacy, Institute of Biology, Freie Universität Berlin Berlin, Germany
| | - Stefanie Krämer
- Behavioural Physiology Group, Department of Biology, Humboldt-Universität zu Berlin Berlin, Germany
| | - Farzad Farkhooi
- Neuroinformatics and Theoretical Neuroscience, Department of Biology, Chemistry and Pharmacy, Institute of Biology, Freie Universität Berlin Berlin, Germany ; Bernstein Center for Computational Neuroscience Berlin, Germany
| | - Bernhard Ronacher
- Behavioural Physiology Group, Department of Biology, Humboldt-Universität zu Berlin Berlin, Germany
| | - Martin P Nawrot
- Bernstein Center for Computational Neuroscience Berlin, Germany
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Schielzeth H, Streitner C, Lampe U, Franzke A, Reinhold K. Genome size variation affects song attractiveness in grasshoppers: evidence for sexual selection against large genomes. Evolution 2014; 68:3629-35. [PMID: 25200798 DOI: 10.1111/evo.12522] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 08/20/2014] [Indexed: 11/27/2022]
Abstract
Genome size is largely uncorrelated to organismal complexity and adaptive scenarios. Genetic drift as well as intragenomic conflict have been put forward to explain this observation. We here study the impact of genome size on sexual attractiveness in the bow-winged grasshopper Chorthippus biguttulus. Grasshoppers show particularly large variation in genome size due to the high prevalence of supernumerary chromosomes that are considered (mildly) selfish, as evidenced by non-Mendelian inheritance and fitness costs if present in high numbers. We ranked male grasshoppers by song characteristics that are known to affect female preferences in this species and scored genome sizes of attractive and unattractive individuals from the extremes of this distribution. We find that attractive singers have significantly smaller genomes, demonstrating that genome size is reflected in male courtship songs and that females prefer songs of males with small genomes. Such a genome size dependent mate preference effectively selects against selfish genetic elements that tend to increase genome size. The data therefore provide a novel example of how sexual selection can reinforce natural selection and can act as an agent in an intragenomic arms race. Furthermore, our findings indicate an underappreciated route of how choosy females could gain indirect benefits.
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Affiliation(s)
- Holger Schielzeth
- Department of Evolutionary Biology, Bielefeld University, 33615 Bielefeld, Germany.
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Lampe U, Reinhold K, Schmoll T. How grasshoppers respond to road noise: developmental plasticity and population differentiation in acoustic signalling. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12215] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Ulrike Lampe
- Department of Evolutionary Biology Bielefeld University Morgenbreede 45Bielefeld 33615 Germany
| | - Klaus Reinhold
- Department of Evolutionary Biology Bielefeld University Morgenbreede 45Bielefeld 33615 Germany
| | - Tim Schmoll
- Department of Evolutionary Biology Bielefeld University Morgenbreede 45Bielefeld 33615 Germany
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17
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Song characteristics and morphological traits in four populations of the grasshopper Chorthippus biguttulus L. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:763-75. [DOI: 10.1007/s00359-012-0746-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 07/31/2012] [Accepted: 07/31/2012] [Indexed: 12/11/2022]
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18
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Ronacher B, Stange N. Processing of acoustic signals in grasshoppers - a neuroethological approach towards female choice. ACTA ACUST UNITED AC 2012; 107:41-50. [PMID: 22728472 DOI: 10.1016/j.jphysparis.2012.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/22/2012] [Accepted: 05/25/2012] [Indexed: 11/18/2022]
Abstract
Acoustic communication is a major factor for mate attraction in many grasshopper species and thus plays a vital role in a grasshopper's life. First of all, the recognition of the species-specific sound patterns is crucial for preventing hybridization with other species, which would result in a drastic fitness loss. In addition, there is evidence that females are choosy with respect to conspecific males and prefer or reject the songs of some individuals, thereby exerting a sexual selection on males. Remarkably, the preferences of females are preserved even under masking noise. To discriminate between the basically similar signals of conspecifics is obviously a challenge for small nervous systems. We therefore ask how the acoustic signals are processed and represented in the grasshopper's nervous system, to allow for a fine discrimination and assessment of individual songs. The discrimination of similar signals may be impeded not only by signal masking due to external noise sources, but also by intrinsic noise due to the inherent variability of spike trains. Using a spike train metric we could estimate how well, in principle, the songs of different individuals can be discriminated on the basis of neuronal responses, and found a remarkable potential for discrimination performance at the first stage, but not on higher stages of the auditory pathway. Next, we ask which benefits a grasshopper female may earn from being choosy. New results, which revealed correlations between specific song features and the size and immunocompetence of the males, suggest that females may derive from acoustic signals clues about condition and health of the sending male. However, we observed substantial differences between the preference functions of individual females and it may be particularly rewarding to relate the variations in female preferences to individual differences in the responses of identified neurons.
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Affiliation(s)
| | - Nicole Stange
- Humboldt-Universität zu Berlin, Department of Biology, Germany
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