Invasion, Distribution, Monitoring and Farmers Perception of Fall Armyworm (Spodoptera frugiperda) and Farm-Level Management Practices in Bangladesh.

Fall armyworm (FAW), Spodoptera frugiperda, is a major pest of maize that was first detected in Bangladesh in 2018 and rapidly spread throughout the maize-growing areas. The presence of FAW was monitored using sex pheromone traps. Farmers' pest management practices were assessed through a questionnaire. The damage is most apparent in the early and late whorl stages. As the crop is grown mostly from November to April, both vegetative and reproductive growth stages remain vulnerable to extensive damage. The survey results showed that 100% of the farmers used pesticides for FAW control, 40.4% handpicked and crushed egg masses, 75.8% handpicked and crushed caterpillars, and only 5.4% used other techniques like applying ash/sand in the funnel of maize. Commonly used pesticides included Spinosad, Emamectin benzoate, Imidacloprid, and others. Thirty-four percent of farmers applied pesticides twice in a season and 48% applied pesticides three times in a season and 54% and 39% of farmers sprayed chemicals at 7-day and 15-day intervals, respectively. FAW causes an average economic loss of 37.7% in maize production without pesticides. Increased use of pesticides to control FAW poses hazards to human health, wildlife, and the environment, and is expensive. Therefore, well-tested agroecological practices and bio-control agents are needed for sustainable FAW management.

Development and Reproductive Capacity of the Miyake Spider Mite Eotetranychus kankitus (Acari: Tetranychidae) at Different Temperatures.

Eotetranychus kankitus (Acari: Tetranychidae) is an important pest of citrus. Assessing life history parameters is crucial to developing an ecologically sound pest management program. Of the many factors that affect life history parameters of herbivorous insects and mites, temperature has the greatest influence on development rate and reproductive potential. We investigated the effects of temperatures from 15 to 40 °C on the demographic parameters of E. kankitus under a long-day (16:8 (L:D) h) photoperiod. The egg-to-adult development time of E. kankitus decreased as the temperature increased from 15 to 32.5 °C. At 35 °C, the female laid eggs that died at the larval stage. The estimated lower thermal thresholds (t0) were 11.01 and 10.48 °C, and the thermal constants (K) were 190.67 and 188.63 degree-days for egg-to-adult females and egg-to-adult males, respectively. The intrinsic optimal temperatures (TØ) for development were 21.79 and 21.74 °C, respectively. The bootstrap-match technique was used in the construction of the life table paramaters. The net reproductive rate (R0) decreased as temperature increased from 20 to 30 °C, but the lowest rate was observed at 15 °C. The intrinsic rate of natural increase (r) increased from 0.0299 day-1 at 15 °C to 0.1822 day-1 at 30 °C. These findings provide a critical theoretical basis for predicting the occurrence of E. kankitus populations under climate warming and for developing appropriate control strategies.

Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility.

BACKGROUND: Evolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher). RESULTS: We sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0-99.9% barrier) at genetic distances of 0.475-0.657, 0.150-0.209 and 0.145-0.210, respectively. Besides, we found asymmetries in reproductive isolation. CONCLUSIONS: The prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this study and previous work, a genetic distance of 0.15-0.21 in mtDNA (COI) appears required for speciation in spider mites. Variations and asymmetries in the degree of reproductive isolation highlight the importance of reinforcement of prezygotic reproductive isolation through incompatibility and the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.

Proteomic evidence for the silk fibroin genes of spider mites (Order Trombidiformes: Family Tetranychidae).

Spider mites are a group of arachnids belonging to Acari (mites and ticks), family Tetranychidae, known to produce nanoscale silk fibers characterized by a high Young's modulus. The silk fibroin gene of spider mites has been computationally predicted through genomic analysis of Tetranychus urticae Koch, but it has yet to be confirmed by proteomic evidence. In this work, we sequenced and assembled the transcriptome from two genera of spider mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor), and combined it with silk proteomics of T. urticae and P. citri to characterize the fibroin genes through comparative genomics and multiomics analysis. As a result, two fibroins were identified, which were different genes than those previously predicted by computational methods. The amino acid composition and secondary structure suggest similarity to aciniform or cylindrical spidroins of spider silk, which partly mirrors their mechanical properties, exhibiting a high Young's modulus. The availability of full-length fibroin sequences of spider mites facilitates the study of the evolution of silk genes that sometimes emerge in multiple lineages in a convergent manner and in the industrial application of artificial protein fibers through the study of the amino acid sequence and the resulting mechanical properties of these silks. SIGNIFICANCE: Here we sequenced and assembled the transcriptome from two genera of spider mites, T. kanzawai and P. citri, and combined it with silk proteomics of T. urticae and P. citri to characterize the fibroin genes through comparative genomics and multiomics analysis. Spider mite silk is especially characterized by its extremely fine nano-scale diameter and high Young's modulus, even exceeding those of spider silks. The availability of full-length fibroin sequences of spider mites facilitates the study of the evolution of silk genes, which independently evolved in mites, insects, and spiders but yet show sequence convergence, and in the industrial application of artificial protein fibers through the study of the amino acid sequence and the resulting mechanical properties of these silks.

Impact of Constant and Fluctuating Temperatures on Population Characteristics of Tetranychus pacificus (Acari: Tetranychidae).

To understand the effect of fluctuating temperature on the population characteristics of Tetranychus pacificus, we determined their life tables under constant temperatures between 10 and 35°C and fluctuating temperatures (12 h per day at each of 5°C above and 5°C below the corresponding constant temperature). Tetranychus pacificus eggs did not hatch when held at a constant temperature of 10°C, whereas 77.6% of the T. pacificus eggs reached an adult life stage at fluctuating temperature 10°C ± 5°C. Female preadult development was faster under fluctuating temperatures 12.5, 15, and 20°C than under constant temperatures, whereas it was not significantly different at temperatures ≥ 22.5°C. The lower developmental thresholds (T0) for female preadult development were 10.24 and 5.73°C for the constant and fluctuating temperatures, respectively, while the thermal summations (K) were 215.10 and 265.64 degree days, respectively. The net reproductive rates (R0) at constant temperatures 15 and 35°C were significantly higher than those at the corresponding fluctuating temperatures. However, for 20, 25, and 30°C, the R0 values were not significantly different between constant and fluctuating temperatures. The intrinsic rate of increase (r) and finite rate of increase (λ) at fluctuating temperatures 10, 20, and 30°C were higher compared to the corresponding constant temperature. However, the values of r and λ at constant 25 and 35°C were higher than those at fluctuating temperature. The differential responses of life history between constant and fluctuating temperatures help to understand the population dynamics of T. pacificus under natural conditions.

Redescription of Panonychus caglei Mellott, 1968, with ontogenetic development (Acari: Tetranychidae).

A redescription of the adult stages of Panonychus caglei Mellott, 1968 (Acari: Tetranychidae), is presented based on new material collected from Japan, and type specimens (holotype and paratypes). Morphological differences in the setation of legs have been reported and measurements of taxonomic characters are added. We also have described the ontogenetic development of the juvenile stages. The ventral idiosomal chaetotaxy in larval stage lacks pregenital and genital setae which are added consecutively through development. The pregenital pair of setae appears in the protonymphs while the first pair of genital setae is firstly observed in the deutonymphal stage.

Complementary description of Panonychus caricae Hatzinikolis, 1984, with the resurrection of the genus Sasanychus Ehara, 1978 (Acari, Prostigmata, Tetranychidae).

A complementary description of Panonychus caricae Hatzinikolis, 1984, is presented based on the morphology of adult female and male individuals collected from fig trees (Ficus sp., Moraceae) in Greece. Morphological differences between Panonychus caricae and two closely related species, Panonychus ulmi (Koch, 1836) and Panonychus hadzhibejliae (Reck, 1947), are discussed. Panonychus caricae can be separated from two other Panonychus species using the length of the female dorsal setae in combination with the ratio between the length of female dorsal opisthosomal setae f2 and h1, and the ratio between the length of dorsal setae sc1 and h1. A phylogenetic maximum likelihood tree was constructed based on the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) from 10 species of the subgenus Panonychus s.str. (including the re-described species P. caricae) and the only two species of the subgenus Sasanychus. The phylogenetic tree indicates that these 12 species are clearly separated from each other. The two subgenera, Panonychus s.str. and Sasanychus, comprise strongly supported monophyletic clades with 98% bootstrap values. The convergence of molecular and morphological data (dorsal setae set on tubercles or not, number of tactile setae on tibiae I and II, and patterns of the dorsocentral striae) suggests that Sasanychus should not be classified under the genus Panonychus. Consequently, molecular and morphological evidence supports the resurrection of the genus Sasanychus, which contains two species, S. akitanus (Ehara) and S. pusillus Ehara Gotoh, as distinct from Panonychus. A key to the world species of Panonychus and Sasanychus is also provided.

A new species of Cenopalpus Pritchard & Baker (Acari: Tenuipalpidae) from Japan, with ontogeny of chaetotaxy and a key to the world species.

A new species of flat mite, Cenopalpus umbellatus sp. nov. (Acari: Trombidiformes: Tenuipalpidae) is described and illustrated based on females, males, deutonymphs, protonymphs and larvae. The morphological ontogeny in idiosomal and leg chaetotaxy is briefly described for all stages. Mite specimens were collected from the leaves of Rhaphiolepis indica var. umbellata Makino (Rosaceae), an evergreen shrub native to Japan. An identification key to the world species of Cenopalpus is also provided.

Effects of Temperature on Demographic Parameters of Bryobia praetiosa (Acari: Tetranychidae).

The clover mite, Bryobia praetiosa Koch (Acari: Tetranychidae), is an agricultural pest, as well as a frequent invader of hospitals and homes. However, its adaptability to different temperatures is not well understood. We used age- and stage-specific life tables to investigate the effects of temperature on demographic parameters of B. praetiosa from 15 to 35°C under a long-day photoperiod (16:8 [L:D] h). The clover mite is a thelytokous species (consisting of only females) due to its infection with the symbiotic bacterium Wolbachia. The egg-to-adult development time of female B. praetiosa decreased as the temperature increased from 15 to 32.5°C. At 35°C, females laid eggs, but no eggs hatched. The lower thermal threshold (t0) and the thermal constant (K) for egg-to-adult females were 8.7°C and 274.1 degree-days, respectively. The intrinsic optimum temperature (TØ) was 22.4°C. The oviposition period decreased with increasing temperature. Fecundity was highest at 20°C and extremely low at 30°C. The net reproductive rate (R0) decreased as the temperature increased from 15 to 30°C, but no significant difference was observed between 15 and 20°C. The intrinsic rate of natural increase (r) varied from 0.0721/d at 15°C to 0.1679/d at 25°C, and then decreased to 0.1203/d at 30°C. These results should be useful in developing management strategies for B. praetiosa.

Spider mite mothers adjust reproduction and sons' alternative reproductive tactics to immigrating alien conspecifics.

Maternal effects on environmentally induced alternative reproductive tactics (ARTs) are poorly understood but likely to be selected for if mothers can reliably predict offspring environments. We assessed maternal effects in two populations (Y and G) of herbivorous arrhenotokous spider mites Tetranychus urticae, where males conditionally express fighting and sneaking tactics in male-male combat and pre-copulatory guarding behaviour. We hypothesized that resident mothers should adjust their reproduction and sons' ARTs to immigrating alien conspecifics in dependence of alien conspecifics posing a fitness threat or advantage. To induce maternal effects, females were exposed to own or alien socio-environments and mated to own or alien males. Across maternal and sons' reproductive traits, the maternal socio-environment induced stronger effects than the maternal mate, and G-mothers responded more strongly to Y-influence than vice versa. G-socio-environments and Y-mates enhanced maternal egg production in both populations. Maternal exposure to G-socio-environments demoted, yet maternal Y-mates promoted, guarding occurrence and timing by sons. Sneakers guarded earlier than fighters in Y-environments, whereas the opposite happened in G-environments. The endosymbiont Cardinium, present in G, did not exert any classical effect but may have played a role via the shared plant. Our study highlights interpopulation variation in immediate and anticipatory maternal responses to immigrants.

Impact of global warming scenarios on life-history traits of Tetranychus evansi (Acari: Tetranychidae).

BACKGROUND: The tomato red spider mite, Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae), is an agricultural pest of solanaceous crops. Although T. evansi is of South American subtropical origin, it has recently expanded its distribution range to many tropical and temperate areas around the world. Its potential distribution range in response to scenarios of global warming was recently modeled, confirming its current and possible future distributions. Here, we experimentally investigated the biological traits of T. evansi in the context of the current and future global warming (2100) scenarios. Using an environmental simulation system, we tested the life-history traits of T. evansi under current summer temperatures (as of June, July, and August 2016) and under expected temperature increases based on two IPCC scenarios: RCP2.6 (+ 1 °C) and RCP8.5 (+ 3.7 °C). The mites were introduced into each scenario on 1 June and their sequential progeny were used for testing in each following month. RESULTS: The mite could develop and reproduce under all scenarios. There was a decrease in the duration of lifespan and female fecundity at RCP8.5 during June and August, but this may be compensated for by the high intrinsic rate of increase, which implies faster population growth and shorter generation time. CONCLUSION: Our study and other reports reveal the high adaptability of T. evansi to a wide range of summer temperatures; this may explain its current distribution. We anticipate that global warming will favor the spread of T. evansi and may further expand its distribution to a large area of the globe. These findings should be of ecological and practical relevance for designing prevention and control strategies.

Morphological identification of Amphitetranychus species (Acari: Tetranychidae) with crossbreeding, esterase zymograms and DNA barcode data.

The genus Amphitetranychus Oudemans (Tetranychidae) consists of only three species, A. quercivorus (Ehara & Gotoh), A. savenkoae (Reck) and A. viennensis (Zacher). The original description of A. savenkoae was extremely simple and had no drawing of the aedeagus; however, a subsequent study described only the aedeagus. The present study investigated all three species in detail using a combination of morphological traits, crossbreeding experiments, esterase zymograms and the mitochondrial cytochrome c oxidase subunit I (COI) gene. Morphological differences in the peritremes and male aedeagi were observed among the three species. Complete reproductive isolation was confirmed in the reciprocal crosses between the morphologically similar A. savenkoae and A. quercivorus (no female offspring were produced). Esterase zymograms differed interspecifically, but not intraspecifically (among individuals in a given species). All three species formed clearly separate clades with 100% bootstrap values in the COI tree, and A. savenkoae was more closely related to A. quercivorus than to A. viennensis, which corresponded to the morphological similarity of their aedeagi and setal counts on tarsi IV. A key to Amphitetranychus species is provided.

Phylogeography of lethal male fighting in a social spider mite.

When males fight for access to females, such conflict rarely escalates into lethal fight because the risks and costs involved, that is, severe injury or death, are too high. The social spider mite, Stigmaeopsis miscanthi, does exhibit lethal male fights, and this male-male aggressiveness varies among populations. To understand the evolution of lethal fighting, we investigated aggressiveness in 42 populations and phylogenetic relationships in 47 populations along the Japanese archipelago. By analysis of the male weapon morph, a proxy for aggressiveness, we confirmed the existence of a mildly aggressive (ML) form, besides the low aggression (LW) and high aggression (HG) forms reported earlier. To evaluate demographic history of these three forms, we employed the approximate Bayesian computation approach using mtCOI sequences and taking into consideration the postlast glacial expansion history of the host plant, Miscanthus sinensis. As results, hierarchical split models are more likely to explain the observed genetic pattern than admixture models, and the ML form in the subtropical region was considered the ancestral group. The inferred demographic history was consistent with the one reconstructed for the host plant in a previous study. The LW form was split from the ML form during the last glacial period (20,000-40,000 years BP), and subsequently, the HG form was split from the ML form at the end of or after the last glacial period (5,494-10,988 years BP). The results also suggest that the mite invaded Japan more than once, resulting in the present parapatric distribution of LW and HG forms in eastern Japan.

New species of the genus Eotetranychus (Acari, Prostigmata, Tetranychidae) from Japan.

Three new species of Eotetranychus (Acari: Tetranychidae) are described and illustrated from Japan. The new species and their host plants are as follows: Eotetranychus palatiensis sp. nov. from Morus australis Poiret (Moraceae), Eotetranychus carpinicolus sp. nov. from Carpinus laxiflora (Siebold et Zuccarini) Blume and C. cordata Blume (Betulaceae), and Eotetranychus linderae sp. nov. from Lindera umbellata Thunberg (Lauraceae). A maximum likelihood tree extracted from the above-mentioned species based on the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) indicated that these species are clearly separated from each other and from selected related species. A key to all Eotetranychus species known in Japan is given.

Mites of the family Parasitidae Oudemans, 1901 (Acari: Mesostigmata) from Japan: a new species of Vulgarogamasus Tichomirov, 1969, and a key to Japanese species.

Vulgarogamasus edurus sp. nov. (Acari: Parasitidae) is described based on females, deutonymphs and males extracted from leaf litter and soil in Ami, Ibaraki Prefecture, Japan. Morphological differences between the new species and its closely related species, Vulgarogamasus fujisanus (Ishikawa, 1972), are recorded based on the examination of type materials. Information about parasitid mites reported in Japanese literature is reviewed, and a key to species is provided.

Phylogeny of the spider mite sub-family Tetranychinae (Acari: Tetranychidae) inferred from RNA-Seq data.

Phylogenetic trees of spider mites were previously obtained using 18S and 28S rRNA genes. Because some of the bootstrap values were relatively low, these trees were unable to completely resolve the phylogeny. Here, we obtained RNA-Seq data for the 72 known species (73 strains) of spider mites to analyze the phylogeny of the sub-family Tetranychinae. The data were de novo assembled into a total alignment length of 790,047 bases corresponding to 264,133 amino acid residues in 652 genes. The sequence dataset was 200 times larger than the data used in the previous study. The new trees were much more robust and more clearly defined the clades of the tribes and the genera of the sub-family Tetranychinae. The tribe Tetranychini was polyphyletic because a monophyletic clade of Eurytetranychini was placed inside it. The six genera from which two or more species were sampled appeared to be monophyletic, but four genera (Schizotetranychus, Eotetranychus, Oligonychus and Tetranychus) appeared to be polyphyletic. These results strongly support the previous molecular inference of the polyphyletic tribes and genera, although the molecular phylogeny of the sub-family Tetranychinae does not fully agree with the current morphology-based taxonomy. The taxonomy of the sub-family Tetranychinae should be revised according to the molecular relationships revealed by this study.

UV-B susceptibility and photoreactivation in embryonic development of the two-spotted spider mite, Tetranychus urticae.

Developmental errors are often induced in the embryos of many organisms by environmental stress. Ultraviolet-B radiation (UV-B) is one of the most serious environmental stressors in embryonic development. Here, we investigated susceptibility to UV-B (0.5 kJ m-2) in embryos of the two-spotted spider mite, Tetranychus urticae, to examine the potential use of UV-B in control of this important agricultural pest worldwide. Peak susceptibility to UV-B (0% hatchability) was found in T. urticae eggs 36-48 h after oviposition at 25 °C, which coincides with the stages of morphogenesis forming the germ band and initial limb primordia. However, hatchability recovered to ~ 80% when eggs irradiated with UV-B were subsequently exposed to visible radiation (VIS) at 10.2 kJ m-2, driving photoreactivation (the photoenzymatic repair of DNA damage). The recovery effect decreased to 40-70% hatchability, depending on the embryonic developmental stage, when VIS irradiation was delayed for 4 h after the end of exposure to UV-B. Thus UV-B damage to T. urticae embryos is critical, particularly in the early stages of morphogenesis, and photoreactivation functions to mitigate UV-B damage, even in the susceptible stages, but immediate VIS irradiation is needed after exposure to UV-B. These findings suggest that nighttime irradiation with UV-B can effectively kill T. urticae eggs without subsequent photoreactivation and may be useful in the physical control of this species.

A new species of spider mite, Oligonychus neocastaneae sp. nov. (Acari: Tetranychidae), from Japan.

A new species Oligonychus neocastaneae sp. nov. is described and illustrated from Castanea crenata Sieb. et Zucc. (Fagaceae). The new species closely resembles Oligonychus castaneae Ehara Gotoh, 2007, which inhabits the same host plant, Castanea crenata, but mainly differs by the aedeagus in having a longer distal portion which forms a small sigmoid and acuminate tip, instead of having a shorter distal portion which ends in a truncate tip. Several differences were also observed between the two species in the leg setal counts of tarsus II in the male and female; the number of tactile setae and solenidia (in parentheses) was 11(1) for the female and male in the new species, but in O. castaneae this count is 12(1) for the female and 12(2) for the male. A maximum likelihood tree based on the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) showed that O. neocastaneae sp. nov. was clearly separated from O. castaneae and other related species. A key to all species of the genus Oligonychus known in Japan is given.

Patterns of reproductive isolation in a haplodiploid - strong post-mating, prezygotic barriers among three forms of a social spider mite.

In speciation research, much attention is paid to the evolution of reproductive barriers, preventing diverging groups from hybridizing back into one gene pool. The prevalent view is that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection and genetic drift in groups that are segregated spatially and/or temporally. Reproductive barriers, however, can also be reinforced by natural selection against maladaptive hybridization. These mutually compatible theories are both empirically supported by studies, analysing relationships between intensity of reproductive isolation and genetic distance in sympatric taxa and allopatric taxa. Here, we present the - to our knowledge - first comparative study in a haplodiploid organism, the social spider mite Stigmaeopsis miscanthi, by measuring premating and post-mating, pre- and post-zygotic components of reproductive isolation, using three recently diverged forms of the mite that partly overlap in home range. We carried out cross-experiments and measured genetic distances (mitochondrial DNA and nuclear DNA) among parapatric and allopatric populations of the three forms. Our results show that the three forms are reproductively isolated, despite the absence of premating barriers, and that the post-mating, prezygotic component contributes most to reproductive isolation. As expected, the strength of post-mating reproductive barriers positively correlated with genetic distance. We did not find a clear pattern of prezygotic barriers evolving faster in parapatry than in allopatry, although one form did show a trend in line with the ecological and behavioural relationships between the forms. Our study advocates the versatility of haplodiploid animals for investigating the evolution of reproductive barriers.

Temperature-Dependent Demography of Two Closely Related Predatory Mites Neoseiulus womersleyi and N. longispinosus (Acari: Phytoseiidae).

Temperature has significant effects on the development, survival, and reproduction of ectothermic organisms. In this study, we examined the effect of temperature on the demographic characteristics of two predatory mite species, Neosciulus womersleyi (Schicha) and N. longispinosus (Evans), reared on Tetranychus urticae Koch. The developmental and reproductive traits of both species were examined at 10 constant temperatures between 15 °C and 37.5 °C. The preadult development time of N. womersleyi and N. longispinosus decreased with increasing temperature until 32.5 °C and 35 °C, respectively. The lower developmental threshold (T0) and thermal constant (K) estimated by using a linear model were 11.61 °C and 69.36 DD for N. womersleyi and 11.92 °C and 61.5 DD for N. longispinosus, respectively. Total preoviposition period and total longevity of females and males of N. womersleyi and N. longispinosus decreased with increasing temperature. The mean generation time (T) first decreased with temperature until 32.5 and 35 °C for N. womersleyi and N. longispinosus, respectively, and then increased at higher temperatures. The R0 and r values first increased with temperature until 32.5 and 30 °C for N. womersleyi and N. longispinosus, respectively, and then decreased at higher temperatures. The R0 and r values for N. longispinosus at 37.5 °C were 0.3 offspring and -0.143 d-1, respectively. These results show that N. longispinosus is less fit than N. womersleyi at 37.5 °C.