Host‐associated divergence in the activity of digestive enzymes in two populations of the gypsy moth Lymantria dispar (Lepidoptera: Erebidae) |
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| Authors: | Jelica Lazarevi? Milena Jankovi?‐Tomani? Uro? Savkovi? Mirko ?or?evi? Slobodan Milanovi? Biljana Stojkovi? |
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| Affiliation: | 1. Department of Insect Physiology and Biochemistry, Institute for Biological Research “Sini?a Stankovi?”, University of Belgrade, Belgrade, Serbia;2. Department of Evolutionary Biology, Institute for Biological Research “Sini?a Stankovi?”, University of Belgrade, Belgrade, Serbia;3. Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University, Brno, Czech Republic;4. Forest Protection Department, Faculty of Forestry, University of Belgrade, Belgrade, Serbia;5. Institute of Zoology, Faculty of Biology, University of Belgrade, Belgrade, Serbia |
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| Abstract: | The gypsy moth is a generalist insect pest with an extremely wide host range. Adaptive responses of digestive enzymes are important for the successful utilization of plant hosts that differ in the contents and ratios of constituent nutrients and allelochemicals. In the present study, we examined the responses of α‐amylase, trypsin, and leucine aminopeptidase to two tree hosts (suitable oak, Quercus cerris, and unsuitable locust tree, Robinia pseudoacacia) in the fourth, fifth, and sixth instars of gypsy moth larvae originating from oak and locust tree forest populations (hereafter assigned as Quercus and Robinia populations, respectively). Gypsy moths from the Robinia forest had been adapting to this unsuitable host for more than 40 generations. To test for population‐level host plant specialization, we applied a two‐population × two‐host experimental design. We compared the levels, developmental patterns, and plasticities of the activities of enzymes. The locust tree diet increased enzyme activity in the fourth instar and reduced activity in advanced instars of the Quercus larvae in comparison to the oak diet. These larvae also exhibited opposite developmental trajectories on the two hosts, i.e. activity increased on the oak diet and decreased on the locust tree diet with the progress of instar. Larvae of the Robinia population were characterized by reduced plasticity of enzyme activity and its developmental trajectories. In addition, elevated trypsin activity in response to an unsuitable host was observed in all instar larvae of the Robinia population, which demonstrated that Robinia larvae had an improved digestive performance than did Quercus larvae. |
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| Keywords: | α ‐amylase development host plant adaptation leucine aminopeptidase phenotypic plasticity trypsin |
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