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1. The univoltine leaf-mining moth, Lirhocofferis quercus Ams., is endemic to Israel, where it spends its 10.5 month larval period feeding only in the leaves of Quercus caffiprinos Webb.2. We compared patterns of egg deposition and sources of larval mortality to test whether oviposition patterns and site preferences confer an enhanced likelihood of larval survival.3. Dominant sources of larval mortality were premature leaf abscission and death from unknown causes, whereas predation, parasitism and intraspecific interference accounted for relatively little larval mortality. 4. Eggs, and thus mines, were aggregated among leaves of host trees even though premature leaf abscission was positively correlated with density of mines per leaf. Interference competition among larvae was the only other density-dependent mortality factor. 5. Oviposition patterns within leaves mitigated the probability of death from larval interference, and probably also from early leaf abscission.6. Despite these density-dependent mortality factors, overall probability of larval survival to pupation was independent of initial density of mines on a leaf. 7. The long larval period allows synchrony between oviposition flights and times of predictable resource availability.

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Efficiencies of food use, growth rates, and consumption rates were measured for larvae of eight tropical insect species, reared upon normal and fertilized Heliconia species (Zingiberales: Heliconiaceae) and Musa sp. (Zingiberales: Musaceae) in Costa Rica. Cephaloleia consanguinea and Chelobasis perplexa (Coleoptera: Chrysomelidae, Hispinae) feed only on Heliconia. Caligo memnon and Opsiphanes tamarindi (Lepidoptera: Brassolidae) are oligophagous, with known hosts in two families of Zingiberales. Sibine apicalis, Sibine sp., and Metraga sp. (Lepidoptera: Limacodidae) and Megalopyge sp. (Lepidoptera: Megalopygidae) are polyphagous, with dicot and monocot hosts.Foliar nitrogen content of natural Heliconia imbricata (x = 1.76%) was lower than that of H. latispatha (x = 3.01%) and Musa sp. (.X = 3.30%). The oligophagous brassolids generally had lower growth rates, lower efficiencies of food use, and lower nitrogen accumulation rates on H. imbricata than on Musa sp.The hispines had lower relative consumption and growth rates than any of the lepidopterans examined on any host or treatment. Growth rates and nitrogen accumulation rates for the hispine species were not affected by host plant fertilization. Efficiencies of nitrogen use declined with increasing foliar nitrogen content for the hispines.Several parameters of food use efficiency were correlated with larval feeding specialization. The specialized hispines and oligophagous brassolids had higher efficiencies of food assimilation and nitrogen use on H. imbricata than did the polyphagous limacodids and megalopygid. Other efficiency indices, such as net growth efficiency, were not correlated with feeding specialization.The hispine Ch. perplexa has one of the longest larval developmental times known for a nondiapausing chrysomelid ( =200 d). Its slow growth is correlated with a low metabolic rate, which we interpret as a physiological adaptation for starvation resistance. Larvae feed only on rolled Heliconia leaves, which are produced infrequently by host plants, and long fasts are a predictable feature of development. Ch. perplexa's eight larval instars are about equal in duration, and closely match the duration of a rolled leafs suitability as food for these larvae. After a rolled leaf unfurls, the larvae must either wait for another on the same plant, or search haphazardly for one on nearby plants. The feeding of Ce. consanguinea larvae is apparently moisture limited in this tropical rain forest, and these larvae also have a high resistance to starvation.The oligophagous brassolids have become pests of banana, which is introduced into the Americas. These species increase growth rates with increased nitrogen content of host tissue. They are infrequent on H. imbricata, which has few chemical defenses against herbivores. Thus, the low nitrogen content of H. imbricata may protect it from some herbivory.