A Hierarchical Model to Predict Time of Flowering of Kiwifruit Using Weather Data and Budbreak Dynamics.

Accurate prediction of flowering times is essential for efficient orchard management for kiwifruit, facilitating timely pest and disease control and pollination interventions. In this study, we developed a predictive model for flowering time using weather data and observations of budbreak dynamics for the 'Hayward' and 'Zesy002' kiwifruit. We used historic data of untreated plants collected from 32 previous studies conducted between 2007 and 2022 and analyzed budbreak and flowering timing alongside cumulative heat sum (growing degree days, GDDs), chilling unit (CU) accumulation, and other environmental variables using weather data from the weather stations nearest to the study orchards. We trained/parameterized the model with data from 2007 to 2019, and then evaluated the model's efficacy using testing data from 2020 to 2022. Regression models identified a hierarchical structure with the accumulation of GDDs at the start of budbreak, one of the key predictors of flowering time. The findings suggest that integrating climatic data with phenological events such as budbreak can enhance the predictability of flowering in kiwifruit vines, offering a valuable tool for kiwifruit orchard management.

Climate Change Helps Polar Invasives Establish and Flourish: Evidence from Long-Term Monitoring of the Blowfly Calliphora vicina.

The isolated sub-Antarctic islands are of major ecological interest because of their unique species diversity and long history of limited human disturbance. However, since the presence of Europeans, these islands and their sensitive biota have been under increasing pressure due to human activity and associated biological invasions. In such delicate ecosystems, biological invasions are an exceptional threat that may be further amplified by climate change. We examined the invasion trajectory of the blowfly Calliphora vicina (Robineau-Desvoidy 1830). First introduced in the sub-Antarctic Kerguelen Islands in the 1970s, it is thought to have persisted only in sheltered microclimates for several decades. Here, we show that, in recent decades, C. vicina has been able to establish itself more widely. We combine experimental thermal developmental data with long-term ecological and meteorological monitoring to address whether warming conditions help explain its current success and dynamics in the eastern Kerguelen Islands. We found that warming temperatures and accumulated degree days could explain the species' phenological and long-term invasion dynamics, indicating that climate change has likely assisted its establishment. This study represents a unique long-term view of a polar invader and stresses the rapidly increasing susceptibility of cold regions to invasion under climate change.

Biology, Thermal Requirements, and Fertility Life Table of Strains of Trichogramma foersteri (Hymenoptera: Trichogrammatidae) in Palpita forficifera (Lepidoptera: Crambidae).

Trichogramma foersteri Takahashi is a parasitoid recently identified in eggs of Palpita forficifera Munroe, considered the main pest of the olive tree in Brazil. The efficiency of a parasitoid is conditioned to several factors such as the temperature. The objective was to study the biology of the immature and adult phases at different constant temperatures (10, 15, 20, 25, and 30 °C), determine thermal requirements, and to elaborate a fertility life table for five strains (R1, R2, R3, R4, and R5) to T. foersteri. At 10 °C, there was no development of T. foersteri. The duration of the egg-adult period (days) was inversely related to temperature, ranging from 32 to 34 days (at 15 °C) to 6.5 to 7.5 days (at 30 °C). The thermal range evaluated did not influence parasitism (parasitism > 57%) and the sex ratio (sr > 0.74). The base temperature (Tt) was similar for all strains (approximately 12 °C), corresponding to a thermal constant (K) of 120.48 to 145.13 degree days. For the adult stage, T. foersteri had the highest rate of parasitism (> 48%) to 15 °C. The emergence rate ranged from 75 to 100%. The thermal range did not influence the sex ratio of the lines (sr > 0.70), but reduced the longevity from 50 days (at 15 °C) to 6 days (at 30 °C). Regarding the fertility life table, all strains of T. foersteri showed biological potential of development and growth in eggs of P. forficifera in the thermal range of 15 to 30 °C, important information for the establishment of biological control programs.

Temperature Dependence for Survival, Development, and Reproduction of the Cactus Cochineal Dactylopius opuntiae (Cockerell).

The effect of temperature on Dactylopius opuntiae (Cockerell) life cycle parameters was evaluated at 20, 23, 26, 32, and 40 ± 1 °C, 65 ± 5% RH, and a photoperiod of 12 L:8 D. Temperatures ranging from 26 °C to 32 °C were suitable for survival, development, and reproduction of D. opuntiae. The total developmental time of females ranged from 94.23 d (20 °C) to 43.55 d (40 °C). The average development time of males from egg to death ranged from 26.97 days at 32 °C to 50.75 days at 20 °C. The probability that a newly laid egg would survive to the adult stage was highest at 26 °C and 32 °C (44-60%). The parthenogenesis in females was not observed during our study. The longest oviposition period was observed when the cochineal was reared at 32 °C (17.97 days), and the highest fecundity was observed at 32 °C (355.29 egg/female). The highest proportion of females (0.80) was observed at 40 °C. According to the age-stage-two-sex life table, the highest value of the intrinsic rate of natural increase (rm) was recorded at 32 °C. The lower developmental thresholds for the total pre-adult female and male and adult female and male stages, were 10.15, 12.21, 10.54, and 21.04 °C, respectively. Dactylopius opuntiae females needed a higher thermal constant (769.23 D°) than males (357.14 D°) to achieve their development and reach the mature adult stage. These findings will be useful for the development of an integrated pest management strategy for D. opuntiae.

Temperature-dependent phenology of Campaea margaritaria (L) (Lepidoptera: Geometridae) derived from field data.

A new phenology model, using thermal sums of triangulated daily temperatures, was applied to the derivation and validation of lower temperature threshold limit and thermal constants of bivoltine Campaea margaritaria (L) from 70 observed flight peak days in The Netherlands (period of 1986-2020) and daily ambient air temperatures of 10 weather stations. Development was assumed to be controlled directly by temperature for the summer generation. During fall a diapause of young larvae was assumed and confirmed. A lower threshold limit of TL = 6.70 ± 0.06 °C was found and a mean thermal winter and summer generation constant of K1,m = 838 ± 9 and K2,m = 848 ± 6 °C.day, respectively, for the reference period of 1993-2013. Generation differences could not be explained with temperature-size rules in ectotherm organisms. Threshold limit and thermal constants depended slightly on the period of derivation indicating short-term plasticity. Flight peak days were calculated with root mean square errors of 2.2-3.0 days for both generations. Changing temperatures of the reference period led to temperature dependences of flight peak days of -6.4 and -8.7 day/°C of the winter and summer generation, respectively. Neglecting physiological changes a complete third generation would require an increase of 3.7 °C, a single generation a decrease of 4.1 °C.

Modeling Temperature-Dependent Development Rate of Neoseiulus cucumeris (Acari: Phytoseiidae) Fed on Two Alternative Diets.

Developmental time of the predatory mite Neoseiulus cucumeris (Oudemans) fed on cattail and almond pollen was determined under laboratory conditions at nine constant temperatures: 10, 15, 20, 25, 27, 30, 32, 35 and 38°C. No development was observed at 10°C. The lower temperature threshold (T0) was estimated to be 10. 97 and 10. 29°C for the almond and cattail pollen, respectively, using the Ikemoto linear model. Thermal constant (K) for pre-adult development of N. cucumeris was 112.8 and 123.5 DD fed on almond and cattail pollen, respectively, using the Ikemoto linear model. The interaction between diet and temperature had a significant effect on the developmental rate of N. cucumeris. The nonlinear Pradhan-Taylor, Janisch/Kontodimas, Briere-1, and Janisch/Rochat models best described the developmental rate of pre-adult stages of N. cucumeris. The estimated Tfast by Pradhan-Taylor model was 31.9 and 33.9°C when fed on almond and cattail pollen, respectively, which was similar to the observed shortest developmental time at 32°C. Our results revealed that N. cucumeris could develop over a wide temperature range (15-35°C), which is a desirable characteristic for a biocontrol agent in biological control programs.

Evaluating the Potential of Using Spodoptera litura Eggs for Mass-Rearing Telenomus remus, a Promising Egg Parasitoid of Spodoptera frugiperda.

Although Telenomus remus, a promising parasitoid of Spodoptera frugiperda, had been successfully reared on the eggs of Corcyra cephalonica in some countries, reports from China have argued that it is infeasible. Notably, studies from China have indicated that Spodoptera litura eggs could be a candidate host. Therefore, to further evaluate the potential of using S. litura eggs as hosts, we compared the development and parasitism of T. remus on the eggs of S. frugiperda and S. litura at temperatures between 20-32 °C. Our results showed that T. remus developed successfully on both host eggs at all of the tested temperatures, and the developmental duration and thermal requirements at each stage were similar between the two host species. The number of parasitized eggs was greater for S. litura than for S. frugiperda. Meanwhile, the emergence rate exceeded 86.6%, and it was significantly higher for S. litura than that for S. frugiperda, except at 29 °C. This study is the first time estimating the thermal requirements of T. remus at each stage. Moreover, we also recorded the morphological characteristics of T. remus at each stage. Our results demonstrate that S. litura eggs are more suitable than S. frugiperda eggs as an alternative host for the mass-rearing of T. remus in China. Understanding the thermal requirements and biological parameters contributes greatly to predicting the generation time and providing a reference for the mass-rearing and storage of the parasitoid.

Creation and Validation of a Temperature-Based Phenology Model for Meloidogyne incognita on Common Bean.

The thermal requirements of Meloidogyne incognita on Phaseolus vulgaris in a set of constant soil temperatures were determined and the phenology model was validated at fluctuating soil temperatures. The base temperature (Tb) and the thermal constant (S) from nematode inoculation to females starting to lay eggs were 11.3 °C and 323 accumulated degree days (DD), respectively; Tb = 10.5 °C and S = 147 DD from egg production to emergence of juveniles; and Tb = 11.1 °C and S = 476 DD for life cycle completion. At fluctuating soil temperatures in pots with the minimum lower than Tb and the maximum higher than To (optimal temperature), the DD calculation was carried out by the average daily temperature-Tb (ADTb) and the single sine method over Tb (SSTb) with horizontal, intermediate, and vertical cutoffs. The most accurate were the ADTb and the SSTb with horizontal and intermediate cutoffs (93-106% of the predicted value) but the vertical underestimated the accumulated DD (75-82% of the predicted value). When fluctuating soil temperatures were between Tb and To in a plastic greenhouse, only the ADTb method was used. Life cycle completion was observed around 465 DD (accuracy between 0.95 and 0.99) at four different transplanting dates.

Biological traits of the predatory mirid Macrolophus praeclarus, a candidate biocontrol agent for the Neotropical region.

The predatory mirid Macrolophus praeclarus is widely distributed throughout the Americas, and is reported to prey upon several horticultural pest species. However, little is known about its biology, thermal requirements, crop odour preferences, phytophagy, and capability to induce defensive responses in plants. When five temperatures studied (20, 25, 30, 33 and 35°C) were tested and Ephestia kuehniella was used as prey, the developmental time from egg to adult on tomato, was longest at 20°C (56.3 d) and shortest at 33°C (22.7 d). The ability of nymphs to develop to adults decreased as the temperature increased, with the highest number of nymphs reaching the adult stage at 20°C (78.0%) and lowest at 35°C (0%). The lower and upper developmental thresholds were estimated at 11.2° and 35.3°C, respectively. The maximum developmental rate occurred at 31.7°C and the thermal constant was 454.0 ± 8.1 degree days. The highest predation rate of E. kuehniella eggs was obtained at 30°C. In Y-tube olfactory choice tests, M. praeclarus selected tomato, sweet pepper and eggplant odours more frequently than no plant control treatment. Macrolophus praeclarus feeding did not damage tomato plants compared to another zoophytophagous mirid, Nesidiocoris tenuis, which caused necrotic rings. The phytophagy of M. praeclarus induced defensive responses in tomato plants through the upregulation of the jasmonic acid metabolic pathway. The implications of the findings for using M. praeclarus in tomato biological control programmes in the Americas are discussed.

Arthropods life cycle and temperature: Beyond isomorphy hypothesis.

In poikilotherms, developmental time and adult lifespan are biological traits driven by temperature although their underlying physiological mechanisms differ. The developmental theory of ageing predicts a positive correlation between these two traits without confirming a genetic or causal relationship. The developmental rate isomorphy hypothesis established that the proportionality in the duration of each pre-imaginal stage with respect to total developmental time does not vary with temperature. This may have important evolutionary implications. We conducted an analysis with arthropods of agronomic interest to study if the hypothesis could be extended to the total lifespan of poikilotherms, including adult lifespan. We showed that isomorphy could be acceptable for a global description of this relationship. However a general model of power law type is more appropriate for characterizing the relationship between developmental time and adult lifespan. In this model, the shape of the curve is a constant characteristic, but the parameters that control it depend on the functional type of the arthropod (phytophagous, predator or parasitoid). Presumably this power law could be extended to all arthropods of agricultural interest, and more generally to all arthropod.

Do female reproductive stage and phenotype influence thermal requirements in an oviparous lizard?

Reproduction is an energetically costly activity that can alter thermal requirements in Squamata. This phenomenon has been largely studied in many viviparous species; however, little is known about the role of oviparous females in controlling temperature during vitellogenesis and embryo development before oviposition. Diversity of female phenotypes could be associated with diversity of thermoregulatory performance, since thermal requirements are frequently influenced by body shape. Furthermore, studying the thermoregulatory behaviour is fundamental to understand how females regulate their body temperature. Here, we aimed to determine whether reproduction alters thermal requirements in an oviparous model, Tropidurus spinulosus, and if the preferred body temperature and thermoregulatory behaviour vary among reproductive stages and in relation to the female phenotype. We characterized the female phenotypes according to multiple morphological traits (snout-vent length, inter-axillar length, abdominal perimeter, body condition and head width). Reproductive structures were diagnosed by portable ultrasound scanning. To determine body temperatures, the lizards were placed in an open-top terrarium, where a thermal gradient ranging from 18 to 50°C was set up; we also recorded the permanence of individuals in cold, temperate and warm zones during each experiment. Reproductive females preferred higher temperatures and presented lower amplitude in thermal variability than non-reproductive females. Moreover, within reproductive females, females with wide abdominal perimeter and high body condition showed thermal stability. Females with oviductal eggs tended to select higher temperature and also show more thermal stability than females with vitellogenic follicles. The latter females used the temperate zone most frequently and to a lesser degree the warm one, whereas females with oviductal eggs used the temperate and warm zones with similarly high frequency. We conclude that reproductive stage and phenotypic traits influence the selection of preferred body temperatures and thermoregulatory behaviour in T. spinulosus females.

Thermal requirements and estimated number of generations of Neopamera bilobata (Say) in strawberry-producing regions of Brazil / Exigências térmicas e estimativa do número de gerações de Neopamera bilobata (Say) em regiões produtoras de morango do Brasil

ABSTRACT: The thermal threshold and thermal requirements of Neopamera bilobata were determined, and the number of generations that this species may produce in the main strawberry-producing regions of Brazil was estimated. In a climate chamber (70±10% RH and 12h photophase) at 16, 19, 22, 25, 28, or 30±1°C, the development of 120 eggs was monitored until the adult stage, at each temperature. Nymphs were maintained in individual cages and fed on strawberry fruits of the cultivar Aromas. The mean duration and viability of the egg and nymph stages were calculated by estimating the lower and upper developmental thresholds and the thermal constant, and this information was used to estimate the number of generations per year in different strawberry-producing regions of Brazil. The egg-to-adult duration decreased as temperatures increased, up to 28°C (93.4, 83.2, 43.9, and 31.4 days at 19, 22, 25, and 28°C, respectively). Viability of nymphs was highest between 22 and 28°C. At 30°C, the egg-to-adult duration increased (36 days), while the viability decreased (11.11%). The lower egg-to-adult developmental threshold was 15.2°C and the thermal constant was 418.4 degree-days. Calculating the number of generations indicated that the largest number (5.1 generations yr-1) was obtained for the municipality of Jaboti, Paraná, and the smallest for Caxias do Sul, Rio Grande do Sul (1.9 generations yr-1). Our findings demonstrated that important strawberry-producing regions in Brazil are suitable for the development of N. bilobata.

RESUMO: A temperatura base e as exigências térmicas de Neopamera bilobata foram determinadas sendo estimado o número de gerações que a espécie realiza nas principais regiões produtoras de morango no Brasil. Em uma câmara climatizada (UR 70±10% e fotofase de 12h) nas temperaturas de 16, 19, 22, 25, 28 ou 30±1°C, o desenvolvimento de 120 ovos por temperatura foi monitorado até a fase adulta. As ninfas foram individualmente mantidas em gaiolas alimentando-as com frutos de morangueiro da cultivar Aromas. A duração média e a viabilidade da fase de ovo e de ninfa foi calculada estimando-se os valores de temperatura base inferior, temperatura base superior, constante térmica e número provável de gerações anuais que o percevejo completa em diferentes regiões produtoras de morangueiro do Brasil. A duração do desenvolvimento ovo-adulto de N. bilobata diminui com a elevação da temperatura até 28°C (93,4; 83,2; 43,9 e 31,4 dias para 19, 22, 25 e 28°C, respectivamente) apresentando maior viabilidade da fase de ninfa entre 22 a 28°C. A 30°C, a duração da fase ovo-adulto aumentou (36 dias), enquanto a viabilidade diminuiu (11,11%). A temperatura base inferior para o desenvolvimento ovo-adulto foi de 15,2°C e a constante térmica de 418,4 graus dia. O maior número de gerações (5,1 gerações/ano) foi obtido para a cidade de Jaboti, PR, e o menor para Caxias do Sul, RS (1,9 gerações/ano). Os valores estimados demonstram que as regiões de importância na produção do morangueiro no Brasil são aptas ao desenvolvimento de N. bilobata.

Impact of water temperature on the growth and fatty acid profiles of juvenile sea cucumber Apostichopus japonicus (Selenka).

The present study determined the changes in the fatty acid (FA) profiles of juvenile sea cucumber Apostichopus japonicus in response to the varied water temperature. Sea cucumbers with similar size (4.02±0.11g) were cultured for 8 weeks at 14°C, 18°C, 22°C and 26°C, respectively. At the end of the experiment, the specific growth rate (SGR) and the profiles of FAs in neutral lipids and phospholipids of the juvenile sea cucumbers cultured at different temperatures were determined. The SGRs of the sea cucumbers cultured at 26°C significantly decreased 46.3% compared to thos cultured at 18°C. Regression analysis showed that the SGR-temperature (T) relationship can be expressed as SGR=-0.0073T(2)+0.255T -1.0231 (R(2)=0.9936) and the highest SGR was predicted at 17.5°C. For the neutral lipids, the sum of saturated FAs (SFAs), monounsaturated FAs (MUFAs) or polyunsaturated FAs (PUFAs) of the sea cucumbers that were cultured at the water temperature from 18°C-26°C did not change significantly, indicating the insensitivity of FA profiles for the neutral lipids of sea cucumbers in response to increasing water temperature. For phospholipids, the sum of PUFAs in the sea cucumbers dramatically decreased with the gradually increased water temperature. The sum of SFAs and MUFAs of sea cucumbers, however, increased with the gradually elevated water temperature. In particular, the contents of highly unsaturated fatty acids (HUFAs), including eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA), in the phospholipids of the sea cucumbers decreased 37.2% and 26.1%, respectively, when the water temperature increased from 14°C to 26°C. In summary, the sea cucumbers A. japonicus can regulate the FA compositions, especially the contents of EPA and DHA, in the phospholipids so as to adapt to varied water temperature.

Temperature-Dependent Development Modeling of the Phorid Fly Megaselia halterata (Wood) (Diptera: Phoridae).

The effect of temperature on the development of Megaselia halterata (Wood) (Diptera: Phoridae) on A15 variety of button mushroom in the stages of casing and spawn-running was investigated at eight constant temperatures (10, 12.5, 15, 18, 20, 22.5, 25, and 27°C) and developmental rates were modeled as a function of temperature. At 25 and 27°C, an average of 22.2 ± 0.14 and 20.0 ± 0.10 days was needed for M. halterata to complete its development from oviposition to adult eclosion in the stages of casing and spawn-running, respectively. The developmental times of males or females at various constant temperatures were significantly different. Among the linear models, the Ikemoto and Takai linear model in the absence of 12.5 and 25°C showed the best statistical goodness-of-fit and based on this model, the lower developmental threshold and the thermal constant were estimated as 10.4°C and 526.3 degree-days, respectively. Twelve nonlinear temperature-dependent models were examined to find the best model to describe the relationship between temperature and development rate of M. halterata. The Logan 10 nonlinear model provided the best estimation for T opt and T max and is strongly recommended for the description of temperature-dependent development of M. halterata.

The effect of temperature on development of Sarconesia chlorogaster, a blowfly of forensic importance.

PURPOSE: The blowfly Sarconesia chlorogaster (Diptera: Calliphoridae) is of limited forensic use in South America, due to the poorly known relationship between development time and temperature. The purpose of this study was to determine development time of S. chlorogaster at different constant temperatures, thereby enabling the forensic use of this fly. METHODS: Development time of this species was examined by observing larval development at six temperatures (10, 15, 20, 25, 30, 35 °C). The thermal constant (K), the minimum development threshold (t 0), and development rate were calculated using linear regressions of the development time interval at five temperatures (10-30 °C). RESULTS: Development interval from egg to adult varied from 14.2 to 95.2 days, depending on temperature. The t0 calculated for total immature development is 6.33 °C and the overall thermal constant is 355.51 degree-days (DD). Temperature affected the viability of pupae, at 35 °C 100 % mortality was observed. CONCLUSION: Understanding development rate across these temperatures now makes development of S. chlorogaster a forensically useful tool for estimating postmortem interval.

Aspectos biológicos de Chrysoperla raimundoi Freitas & Penny (Neuroptera, Chrysopidae) / Biological aspects of Chrysoperla raimundoi Freitas & Penny (Neuroptera, Chrysopidae)

Os crisopídeos são importantes predadores e são encontrados em diversos agroecossistemas. A temperatura é um dos fatores determinantes para o desenvolvimento dos insetos, sendo que existe um gradiente de variação aceitável para cada espécie. Portanto, objetivou-se com este estudo verificar a influência de diferentes temperaturas sobre o desenvolvimento embrionário e pós-embrionário de C. raimundoi assim como verificar as conseqüências nas diferentes gerações. As fases jovens foram criadas em três ambientes com temperaturas constantes de 19,0, 25,0 e 31,0ºC e em um ambiente externo sem controle dos fatores abióticos. Foram observados a duração do período embrionário, do primeiro, segundo e terceiro ínstares, a duração do período larval, pupal e ovo-adulto, assim como, a sobrevivência em cada estágio, estádio e a porcentagem de emergência. O desenvolvimento embrionário e pós-embrionário diferiu entre as gerações F2 e F4. Quanto à influência de diferentes temperaturas para a geração F2, os indivíduos criados a 31,0ºC demonstraram redução na taxa de desenvolvimento com relação aos outros dois ambientes. Para a geração F4, observou-se que as diferentes temperaturas influenciaram no desenvolvimento, sendo que a 19,0ºC houve prolongamento do mesmo.

The green lacewings are important predators and are found in several agroecosystems. The temperature is one of the decisive factors for the development of insects, and there is an acceptable variation gradient for each species. Therefore, the purpose of this study was not only to check the influence of different temperatures on the embryonic and post-embryonic development of Chrysoperla raimundoi, as well as check the consequences in the different generations. The immature stages were reared at four different environmental conditions, three of them with constant temperatures (19,0, 25,0 e 31,0ºC) and the fourth rearing place was external to the laboratory without control of the abiotic factors. The duration of the embryonic period, first, second and third larval instar, pupal stage, and from egg to adult were evaluated; also the survival rate of each instar and stage and the emergence rate were calculated. The embryonic and post embryonic development differed between the generations F2 and F4. Also, the influence of different temperatures for the generation F2 among individuals created at 31,0ºC showed reduction on the development rate regarding the other two environments. It was possible to observe that the generation F4 has its development influenced by different temperatures, and the 19,0ºC temperature prolonged its development.

Efeitos da temperatura e do alimento no desenvolvimento de Dysdercus maurus Distant (Hemiptera, Pyrrhocoridae) / Effects of temperature and food on the development of Dysdercus maurus Distant (Hemiptera, Pyrrhocoridae)

Dysdercus maurus Distant, 1901 (Hemiptera, Pyrrhocoridae) é uma importante praga de Gossypium spp. (algodoeiro), Citrus Sinensis Osbeck (Rutaceae) (laranjeira) e Citrus reticulata (Rutaceae) (tangerineira), além de sementes de Chorisia speciosa St. Hil. (paineira). Este trabalho objetivou avaliar os efeitos da temperatura e do alimento no desenvolvimento de D. maurus. Foram realizados oito tratamentos, seis em que os percevejos foram alimentados com sementes de paineira e mantidos a 15, 18, 20, 25 e 30 ± 1ºC, UR 80 ± 3 por cento e fotofase de 12 h ou em condições ambientais de laboratório (23,5 ± 2,6ºC, UR 73,3 ± 9,9 por cento), e dois em que foram alimentados com sementes de algodão variedade IAC-22 e mantidos a 25 e 30ºC. Em todos os tratamentos foram observados cinco estágios imaturos. O aumento da temperatura proporcionou diminuição do tempo de desenvolvimento. A temperatura de 15ºC foi letal para ovos e ninfas de D. maurus. A menor mortalidade de ninfas ocorreu quando os percevejos foram alimentados com sementes de algodão a 25ºC (24,07 por cento). A menor temperatura base (Tb) foi obtida para o 1º ínstar (11,54ºC) e a maior para o 2º ínstar (15,33ºC). As fêmeas de D. maurus necessitam de maior quantidade de graus-dias (329,93 graus-dias) que os machos (300,49 graus-dias) para atingir o estádio adulto.

Dysdercus maurus Distant, 1901 (Hemiptera, Pyrrhocoridae) is an important pest on Gossypium spp. (cotton tree), Citrus sinensis Osbeck (Rutaceae) and Citrus reticulata Blanco (Rutaceae) crops. This insect also feeds on seeds of Chorisia speciosa St. Hil. (Bombacaceae). This work aimed to evaluate the effects of temperature and food on the development of D. maurus. Eight treatments were carried out, in six of them bugs were fed with seeds of C. speciosa and kept at 15, 18, 20, 25 and 30 ± 1ºC, 80 ± 3 percent RH and 12h photophase or in laboratory conditions (23.5 ± 2.6ºC, 73.3 ± 9.9 percent RH), and in the other two treatments bugs were fed with seeds of cotton variety IAC-22 and kept at 25 or 30ºC. In all treatments five immature stages were observed. The increase of temperature caused reduction in the developmental time. The temperature of 15ºC disabled nymphal eclosion and was also lethal to those nymphs ecloded at other temperatures. The lower mortality of nymphs occurred in the temperature of 25ºC with cotton as food (24.07 percent). The lower threshold temperature (Tb) occurred for the 1st instar (11.54ºC) and the higher for the 2nd instar (15.33ºC). The females of D. maurus required more degree-days (329.93 degree-days) than males (300.49 degree-days) until adult emergence.

Exigências Térmicas e Estimativa do Número de Gerações de Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae) / Thermal Requirements and Estimate of the Number of Generations of Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae)

Argyrotaenia sphaleropa (Meyrick) is often found attacking Diospyros kaki fruits in southern region of Brazil. Duration and viability of the periods (eggs, larvae and pupae) and lifespan of the pest was studied under laboratory conditions in different temperatures. The experiment was conducted in climatic chambers under 60±10 percent RH and 14h photophase, at temperatures of 14, 18, 20, 22, 25, 28 and 30°C, using artificial diet. Larval eclosion occurred in 5.9 to 25.4 days and larval period ranged from 13.9 to 91.1 days at 30 and 14°C, respectively. A variation of 6.4 (30°C) to 28.3 (14°C) and 26.5 (30°C) to 143.4 (14°C) days was observed for pupal phase and lifespan. Eggs, larvae and pupae viability was always higher than 75 percent while the lower total viability was 64.8 percent at 18°C. For eggs, larvae, pupae and total cycle, the threshold temperature and thermal requirements were respectively 10.8, 10.9, 10.0 and 11.0°C and 104.3, 251.4, 114.9 and 473.3 degree days. For A. sphaleropa the occurrence of the 4.1 and 14.7 generations per year were estimated in the field and in the laboratory (30°C), respectively. Temperatures of 14 and 18°C were less favorable for the insect development, with increase in time of development and decrease in survivorship.

Lagartas de Argyrotaenia sphaleropa (Meyrick) são comumente encontradas atacando frutos de caqui, Dispyros kaki L., na região da Serra do Rio Grande do Sul. Neste trabalho a duração e a viabilidade das fases (ovo, lagarta e pupa) e do período de desenvolvimento total (ovo-adulto) de A. sphaleropa foram estudadas em diferentes temperaturas. O experimento foi conduzido em câmaras climatizadas a UR de 60±10 por cento e fotofase de 14h, nas temperaturas de 14, 18, 20, 22, 25, 28 e 30°C, alimentando-se as lagartas com dieta artificial. A duração das fases de desenvolvimento foi, em geral, inversamente proporcional à temperatura. O período embrionário variou de 5,9 (30°C) a 25,4 (14°C) dias. A duração da fase de lagarta foi 13,9 e 91,1 dias, nas temperaturas de 30 e 14°C, respectivamente. Ocorreu variação de 6,4 (30°C) a 28,3 (14°C) e 26,5 (30°C) a 143,4(14°C), respectivamente, para a fase de pupa e para todo o período de desenvolvimento. A viabilidade das fases de ovo, lagarta e pupa foi sempre superior a 75 por cento. Contudo, apesar não ter havido diferença estatística entre as temperaturas, a 14 e 18°C, a viabilidade para todo o período de desenvolvimento foi baixa, de 69,6 e 64,8 por cento, respectivamente. Para as fases de ovo, lagarta, pupa e período de desenvolvimento total os valores das temperaturas base (Tb) e das constantes térmica foram de 10,8; 10,9; 10,0 e 11,0°C e 104,3; 251,4; 114,9 e 473,3, respectivamente. Foi estimada a ocorrência de 4,1 gerações anuais de A. sphaleropa em campo e 14,7 gerações anuais em laboratório (30°C). As temperaturas de 14 e 18°C foram menos adequadas para o desenvolvimento do inseto devido ao aumento do período de desenvolvimento e redução na sua viabilidade.