Fitness components in the relationship between Rhopalapion longirostre (Olivier, 1807) (Insecta: Coleoptera: Apionidae) and Alcea rosea (Linnaeus, 1758) (Malvaceae). Analysis of infestation balance of a herbivorous weevil and its host plant (original) (raw)
Related papers
2015
Multivariate statistics (principal components analysis, path analysis) were used to investigate fitness components of the interactions between the weevil Rhopalapion longirostre (Olivier, 1807), Apionidae, Coleoptera and its host plant Alcea rosea (Linnaeus, 1758), Malvaceae. We focused on the activities of the larvae such as the choice of seeds for consumption, the preparation of seed chambers as a site for pupation, as well as the construction of escape holes through which the adults later emerge. The analyses revealed that the optimal conditions for successful development of the weevils depended on the availability of seed capsules characterized by a high number of well developed seeds, few undeveloped and few spoiled seeds. The high number of larvae, pupae and not emerged adults found in the seed capsules corresponds with the successful emergence of adults. Egg deposition by the females in appropriate flower buds of the host plant, together with larval contribution to overall re...
2021
1. The reproduction of specialised endophagous insects relies on a fine temporal synchronization between the insect and its host plant phenology. 2. Since the spatial distribution and local prevalence of specialised insects depend on both environmental conditions and biotic interactions, in this study, we assessed whether the life cycle of the predispersal seed feeding weevil, Hemicolpus abdominalis (Curculionidae), is synchronised with the reproductive phenology of its host plant, Tocoyena formosa (Rubiaceae) in the Brazilian Cerrado. Following an ecological niche modelling approach, we also tested whether the predicted distribution of this specialised weevil matches that of its host plant. 3. We observed a tight synchronization between the weevil reproduction and its host plant reproductive phenology. After emergence from the fruits, adult weevils enter in reproductive diapause, with reproductive development resuming in the next reproductive season, which indicates the univoltism of this species. 4. There was a high spatial congruence in the distribution of H. abdominalis and its host plant. Since the reproduction of H. abdominalis is synchronised with the host plant phenology, temporal mismatches between the weevil life cycle, and plant reproduction may affect the long-term population prevalence of the insect. 5. The life cycle of the predispersal seed feeding weevil, H. abdominalis, depends on a close match with the host plant reproductive phenology, whose fruit production is entirely dependent on long-tongued hawkmoth pollinators. Hence, we highlight the importance of both biotic and abiotic conditions in shaping the distribution range of a specialised endophagous insect.
Acta Oecologica-international Journal of Ecology, 1999
Palm pollination can be quite diverse but has been poorly studied. This paper describes the life cycle of Derelomus chamaeropsis, a Coleoptera that inhabits the inflorescences of the Mediterranean dwarf palm Chamaerops humilis. D. chamaeropsis is specific to Chamaerops inflorescences, where it eats pollen and the rachis of inflorescences on pistillate plants. They usually lay eggs only on staminate inflorescences where larvae develop and bore into the inflorescence rachis. Larvae do not develop on pistillate inflorescences, except for cases with almost no fruit development. Pistillate plants can thus protect themselves from weevil predation. When visiting pistillate inflorescences, weevils can feed on rachis but usually do not find the brood place reward. Pollination is thus by deceit and weevils should be selected to avoid pistillate inflorescences. D. chamaeropsis pupate within the rachis of staminate inflorescences, but disperse before collecting pollen, thus staminate plants do not have an individual advantage in breeding weevils. However, because larvae develop on dead tissues, the costs of larval development are likely to be low for the plant. This study provides a new example of pollination symbiosis where the pollinator develops on the plant it pollinates, and illustrates how the evolutionary functioning of such relationships can be diverse. © 1999 Éditions scientifiques et médicales Elsevier SAS
Weevil Impacts of Wild Indigo Weevil on Seed Production in Longbract Wild Indigo
2010
Seeds of many species of Baptisia are eaten by larvae of the wild indigo weevil Apion rostrum, impacting plant fitness and compromising prairie restoration activities. We examined the impacts of A. rostrum predation on seed output in a commercial seed production population of longbract wild indigo Baptisia bracteata in southeastern Minnesota. Predehiscent seed pods (n = 673) were collected from 15 plants in September 2007, measured (total pod length), and examined for intact seeds, damaged seeds, and weevils. Adult weevils were present in 46% of pods examined, averaging 1.53 weevils/predated pod. More than 40% of predated pods contained two or more weevils. Pods contained an average of 9 seeds each, but two-thirds of the seeds failed to develop properly or were damaged by predation and/or fungus (possibly introduced by ovipositing weevils). Non-predated seed pods averaged 10 X more undamaged seeds than did predated seed pods (5.14 vs. 0.48 seeds/pod). Predated pods averaged 0.25 cm ...
Functional Ecology, 2001
1. Natural enemies are likely to influence the interactions between herbivorous insects and their host plants. In particular, selection exerted by natural enemies could favour host-plant switches and cause, or maintain, oviposition preference for a host species that is nutritionally inferior to another acceptable host. 2. In a previous study, it was shown that larvae of the leaf beetle Oreina elongata perform better on Adenostyles alliariae (Asteraceae) than on Cirsium spinosissimum (Asteraceae). Moreover, A. alliariae provides larval and adult beetles with sequestrable chemical defences. However, in the field, egg densities are much higher on C. spinosissimum than on adjacent A. alliariae . 3. In this study, it was investigated whether this oviposition pattern could be maintained by C. spinosissimum , providing the eggs of O. elongata with better protection from natural enemies. In a field experiment, the survival of eggs was quantified on plants of each of the two species, with and without enemy exclusion. 4. Egg survival was equal for both host species when enemies were excluded from the plants, but it was higher on C. spinosissimum than on A. alliariae when enemies were allowed to the plants. It was also experimentally tested whether the higher egg densities observed in the field on C. spinosissimum are actually due to oviposition preference by the beetle. In a no-choice test, females laid more eggs on C. spinosissimum than on A. alliariae . 5. It can thus be confirmed that C. spinosissimum is really preferred for oviposition and it is concluded that this preference is likely to be maintained, at least partly, by a higher egg survival on C. spinosissimum due to enemy-free space provided by this host plant.
Acta Oecologica-international Journal of Ecology, 2001
Many morphological features of fruits are important factors affecting predispersal seed predation by insects. This paper analyses the predispersal seed predation process of a major predator (a Noctuidae lepidopteran larvae) in loculate fruits of a bushy perennial plant, Cistus ladanifer. The main aim of the study is to assess the potential effect of internal valvae (which partition groups of seeds) in the intraspecific competition between larvae in multiple-infested fruits. Our results show that larvae do not reject already infested fruits, but they avoid the proximity of other larvae within the fruit, keeping an average minimum distance of one locule. In multiple-infested fruits, larval mortality increases and the proportion of seeds consumed by each larvae decreases. In those situations in which valvae keep apart larvae within a fruit, these only suffer the cost of exploitation competition with a low acquisition of resources. However, when all valvae between them are pierced by the larvae, competition switches to an interference component and larval mortality increases markedly. The existence of valvae within a fruit allows larvae to diminish the cost of intraspecific competition, obtaining high life expectancies (70%), even in triple-infested fruits. © 2001 Éditions scientifiques et médicales Elsevier SAS Cistus ladanifer / intraspecific competition / loculate fruits / seed predation *Correspondance and reprints: Fax: +34 1 3945081.
The effect of spatial scale on interactions between two weevils and their food plant
Acta Oecologica, 1999
The effect of spatial scale on the interactions between the weevils Gymnetron pascuorum Gyll. and Mecinus pyraster Herbst and their host plant, ribwort plantain Plantago lanceolata L., was studied. Both weevils developed in plantain seedheads but occupied different niches within the seedhead. Seedheads were sampled annually from 162 plants at each of two experimental sites consisting of a series of habitat patches of two distinct sizes. Data were analysed from three site-years. Our results suggest that the density of available seedheads varied among years and this had a direct effect on abundance. M. pyraster, which develops in the stem within the seedhead, was more sensitive to changes in seedhead density than was G. pascuorum, which develops within the seeds themselves. The presence of a hedgerow along one side of the experimental site affected the pattern of colonisation of newly-created habitat patches by G. pascuorum but not by M. pyraster. Changes in spatial scale did not affect the variability of seedhead and insect densities. G. pascuorum had an aggregated distribution at all the spatial scales considered, but the distribution of M. pyraster was very scale dependent. The distributions of the two weevil species were positively associated amongst infested plants but not amongst infested seedheads. Behavioural and ecological factors that could explain the results of the data analyses are discussed.
Biological Invasions, 2011
Mechanisms underlying invasive species impacts remain incompletely understood. We tested the hypothesis that priority resource access by an invasive biocontrol weevil, Rhinocyllus conicus, intensifies and alters the outcome of competition with native floral herbivores over flower head resources of the non-target, native host plant Cirsium canescens, specifically with the predominant, synchronous tephritid fly Paracantha culta. Four main results emerged. First, we documented strong, asymmetric competition, with R. conicus out-competing P. culta. Second, weevil priority access to floral resources accelerated competitive suppression of P. culta. Evidence for competitive suppression with increased weevil priority included decreases in both the numbers and the total biomass of native flies, plus decreases in individual P. culta fly mass and, so, potential fitness. Third, we found evidence for three concurrent mechanisms underlying the competitive suppression of P. culta by R. conicus. Prior use of a flower head by R. conicus interfered with P. culta pre-oviposition behavior. Once oviposition occurred, the weevil also reduced fly post-oviposition performance. Preemptive resource exploitation occurred, shown by the significant effect of flower head size on the total number of insects developing and in the magnitude of R. conicus effects on P. culta. Interference also occurred, shown by a spatial shift of surviving P. culta individuals away from the preferred receptacle resources as R. conicus priority increased. Finally, fourth, using an individual-based model (IBM), we found that the competitive interactions documented have the potential for imposing demographic consequences, causing a reduction in P. culta population sizes. Thus, priority resource access by an invasive insect increased competitive impact on the predominant native insect in the invaded floral guild. This study also provides the Electronic supplementary material The online version of this article (
Entomologia Experimentalis et Applicata, 2019
It has been shown that intraspecific competition and resource quality may affect life-history traits of insects, such as body size, fecundity, and survival. However, intraspecific competition and resource quality may interact with each other. The study of such interacting effects is crucial for understanding the influence of these ecological variables on the selection of specific life-history traits. Here, we investigated whether the interaction between intraspecific larval competition and variation in resource quality affects adult emergence and survival, egg size, fecundity, body size, and sexual size dimorphism (SSD) of the seed-feeding beetle Acanthoscelides macrophthalmus (Schaeffer) (Coleoptera: Chrysomelidae: Bruchinae) when infesting Leucaena leucocephala (Lam.) De Wit (Fabaceae), its host plant. In the laboratory, beetles were reared on seeds that differed in quality (e.g., different hardness, seed size, water content), in the presence or absence of larval competition. Body size and SSD did not differ between treatments (with and without competition), nor were they affected by varying resource quality. Females subjected to competition during the larval stage and females emerging from seeds of higher quality, displayed the highest fecundity. The proportion of emergent adults was higher in the absence of competition. In addition, larger eggs were laid on the low-quality resource in the absence of competition, showing a trade-off between egg size and egg number. Adult survival differed among treatments and resource qualities, suggesting a higher investment in adult survival for individuals emerging from seeds of low quality in the presence of competition. Whether changes in specific traits could be selected for in detriment of others will depend on the strength of intraspecific competition, the variation in resource quality, and the plasticity in the life-history traits investigated. This needs further clarification.