Effects of synchronization with host plant phenology occur early in the larval development of a spring folivore

2006 ◽  
Vol 84 (4) ◽  
pp. 628-633 ◽  
Author(s):  
B.C. Jones ◽  
E. Despland

Early spring feeding Lepidoptera depend on synchronization of larval emergence with host plant phenology for optimal growth and development. Physical and chemical characteristics of foliage change over the course of the growing season, and a delay in larval emergence therefore results in larvae foraging on lower quality food. We examine the effect of synchronization of larval emergence with leaf phenology on the entire larval stage of the forest tent caterpillar, Malacosoma disstria Hübner, 1820 (Lepidoptera: Lasiocampidae). Caterpillars were reared from egg hatch to pupation on trembling aspen, Populus tremuloides Michx; 10 days separated egg hatch in the early and late treatments. Late-hatching caterpillars experienced reduced growth in the early instars, but growth in the later instars did not differ between treatments. Reduced growth early in development resulted in both prolongation of the larval stage through the occurrence of additional instars, and lower pupal mass. Aspen foliage quality changes rapidly during leaf expansion, and the late-hatching caterpillars likely missed the narrow window of opportunity for young larvae to feed on high-quality developing foliage. This study demonstrates the importance of early-instar ecology in Lepidoptera.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jonathan T. D. Finch ◽  
Sally A. Power ◽  
Justin A. Welbergen ◽  
James M. Cook

Abstract Background For specialised pollinators, the synchrony of plant and pollinator life history is critical to the persistence of pollinator populations. This is even more critical in nursery pollination, where pollinators are obligately dependant on female host plant flowers for oviposition sites. Epicephala moths (Gracillariidae) form highly specialised nursery pollination mutualisms with Phyllanthaceae plants. Several hundred Phyllanthaceae are estimated to be exclusively pollinated by highly specific Epicephala moths, making these mutualisms an outstanding example of plant–insect coevolution. However, there have been no studies of how Epicephala moths synchronise their activity with host plant flowering or persist through periods when flowers are absent. Such knowledge is critical to understanding the ecology and evolutionary stability of these mutualisms. We surveyed multiple populations of both Breynia oblongifolia (Phyllanthaceae) and it’s Epicephala pollinators for over two years to determine their phenology and modelled the environmental factors that underpin their interactions. Results The abundance of flowers and fruits was highly variable and strongly linked to local rainfall and photoperiod. Unlike male flowers and fruits, female flowers were present throughout the entire year, including winter. Fruit abundance was a significant predictor of adult Epicephala activity, suggesting that eggs or early instar larvae diapause within dormant female flowers and emerge as fruits mature. Searches of overwintering female flowers confirmed that many contained pollen and diapausing pollinators. We also observed diapause in Epicephala prior to pupation, finding that 12% (9/78) of larvae emerging from fruits in the autumn entered an extended diapause for 38–48 weeks. The remaining autumn emerging larvae pupated directly without diapause, suggesting a possible bet-hedging strategy. Conclusions Epicephala appear to use diapause at multiple stages in their lifecycle to survive variable host plant phenology. Furthermore, moth abundance was predicted by the same environmental variables as male flowers, suggesting that moths track flowering through temperature. These adaptations may thereby mitigate against unpredictability in the timing of fruiting and flowering because of variable rainfall. It remains to be seen how widespread egg diapause and pre-pupal diapause may be within Epicephala moths, and, furthermore, to what degree these traits may have facilitated the evolution of these highly diverse mutualisms.


2021 ◽  
Author(s):  
Jonathan T. D. Finch ◽  
Sally A. Power ◽  
Justin A. Welbergen ◽  
James M. Cook

AbstractFor pollinating insects that visit just a single flowering species, the co-occurrence of flowers and insects in time is likely to have critical implications for both plant and pollinator. Insects often utilise diapause to persist through periods in which resources are unavailable, timing their re-emergence by responding to the same environmental cues as their host plants. The obligate pollination mutualisms (OPMs) between Epicephala moths (Gracillariidae) and their leaf flower host plants are some of the most specialised interactions between plants and insects. However, to date there have been very few studies of Epicephala moth lifecycles and none of how they synchronise their activity with the flowering of their host plants. Breynia oblongifolia (Phyllanthaceae) is known to be exclusively pollinated by two highly specific species of Epicephala moth (Gracillariidae). We surveyed populations of both the host plant and it’s pollinators over multiple years to determine their annual phenology and then modelled the climatic factors that drive their activity. Using our newly gained knowledge of moth and host plant phenology, we then looked for evidence of diapause at both the egg and pre-pupal stages. Our phenology surveys showed that although female flowers were present throughout the entire year, the abundance of flowers and fruits was highly variable between sites and strongly associated with local rainfall and photoperiod. Fruit abundance, but not flower abundance, was a significant predictor of adult Epicephala activity, suggesting that eggs or early instar larvae diapause within dormant flowers and emerge as fruits mature. Searches of overwintering flowers confirmed this, with many containing evidence of pollen and diapausing pollinators. We also observed the behaviour of adult Epicephala prior to pupation and found that ~10% of the Autumn emerging Epicephala enter diapause, eclosing to adulthood after 38-56 weeks. The remaining 90% of autumn emerging adults pupate directly with no diapause, suggesting a bet hedging strategy for adult emergence. As such, Epicephala moths appear to utilise diapause at multiple stages in their lifecycle, and possibly bet hedging, in order to deal with variable flowering phenology and climatic unpredictability.


2002 ◽  
Vol 20 (3) ◽  
pp. 138-142
Author(s):  
William E. Klingeman

Abstract The bagworm (Thyridopteryx ephemeraeformis (Haworth)) is a polyphagous, native pest of numerous deciduous and evergreen ornamental plants. Bagworm larvae were used to investigate host plant susceptibility among ten species and cultivars of maples that are economically important and commonly encountered in landscapes in the eastern United States. Data analyses from 48-hour choice assays, conducted in the laboratory during 2000 and 2001, indicated that differences existed among maples for bagworm feeding preferences and host plant susceptibility. Results from the 48-hour trials were not as accurate as seasonal no-choice assays, however. No-choice assays during both seasons quantified resistance among maples that limited larval bagworm survival and development. Measurements of larval feeding injury demonstrated resistance in paperbark maple (Acer griseum (Franch.) Pax) and trident maple (A. buergerianum Miq.) when compared with other maples. Laboratory results were corroborated during 2001 by a no-choice field assay, in which early instar bagworm larvae performed well on the majority of maples. In contrast, paperbark maple and trident maple were resistant to bagworm feeding, while ‘Autumn Blaze’ Freeman maple (A. x freemanii E. Murray), a hybrid cross obtained by breeding A. rubrum with A. saccharinum, showed moderate resistance.


2010 ◽  
Vol 24 (5) ◽  
pp. 1103-1109 ◽  
Author(s):  
Margriet van Asch ◽  
Riita Julkunen-Tiito ◽  
Marcel E. Visser

2019 ◽  
Vol 89 (3) ◽  
pp. 829-841
Author(s):  
Adam Ekholm ◽  
Ayco J. M. Tack ◽  
Pertti Pulkkinen ◽  
Tomas Roslin

2019 ◽  
Vol 112 (4) ◽  
pp. 1587-1597 ◽  
Author(s):  
Juan Pedro Raul Bouvet ◽  
Alberto Urbaneja ◽  
César Monzó

Abstract The Spirea citrus aphid, Aphis spiraecola Patch, and the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), are key pests of clementine mandarines in the Mediterranean basin. Severity of aphid infestations is determined by environmental variables, host plant phenology patterns, and the biological control exerted by their associated natural enemies. However, there is no information about the role these limiting and regulating factors play. Aphid densities, citrus phenology, and associated predators that overwinter in the crop were monitored weekly throughout two flush growth periods (February to July) in four clementine mandarin groves; relationships between these parameters and environmental variables (temperature and precipitation) were studied. Our results show exponential increase in aphid infestation levels to coincide with citrus phenological stages B3 and B4; shoots offer more space and nutritional resources for colony growth at these stages. Duration of these phenological stages, which was mediated by mean temperature, seems to importantly determine the severity of aphid infestations in the groves. Among those studied, the micro-coccinellids, mostly Scymnus species, were the only group of predators with the ability to efficiently regulate aphid populations. These natural enemies had the highest temporal and spatial demographic stability. Aphid regulation success was only achieved through early presence of natural enemies in the grove, at the aphid colonization phase. Our results suggest that conservation strategies aimed at preserving and enhancing Scymnus sp. populations may make an important contribution to the future success of the biological control of these key citrus pests.


2013 ◽  
pp. n/a-n/a ◽  
Author(s):  
Junichi Yukawa ◽  
Kohjin Nakagawa ◽  
Tetsumi Saigou ◽  
Takahiro Awa ◽  
Takeshi Fukuda ◽  
...  

1993 ◽  
Vol 22 (2) ◽  
pp. 388-396 ◽  
Author(s):  
Susan Torgerson How ◽  
Warren G. Abrahamson ◽  
Timothy P. Craig

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