Effect of flour and pasta debris on larval development of Rhyzopertha dominica

The development of Rhyzopertha dominica (F.) larvae on different types of flour and on pasta debris was evaluated under laboratory condition. Tests were carried out on wheat flour, semolina, wheat bran, corn meal, corn starch, rice flour, buckwheat flour, chickpea flour, almond flour, chestnut flour, potato starch, and pasta debris. Two layers of flour or pasta debris, 3 and 6 mm high, were placed in Petri dishes and 20 first instar larvae were put into the middle of the substrate. Four replicates were carried out for each combination of substrate, particle size, and thickness of the layer. The emergence of adults was assessed daily. Chestnut flour and semolina permitted the development of larvae in a period of time similar to that observed in cereal kernels while chickpea flour and wheat flour were less appropriate food; in fact, only 25% of larvae underwent complete development into adults. In the case of corn meal, rice flour, and wheat bran, only 5% of adults emerged, while larvae were unable to develop on corn starch and potato starch. Although R. dominica is a well-known pest of pasta, pasta debris was less suitable for the development of larvae, as few adults emerged and a longer development time was observed. A three-millimeter layer of suitable food was sufficient for the development of larvae, although a higher number of adults was observed in the 6 mm layer

Heteroptera collected in Valsesia, Northern Italy

The survey of Heteroptera carried out in 2016 along the nature path \u201cBosco dei Tigli\u201d (Lime Trees Wood) in Piode (Piedmont, 900 m a.s.l.), highlighted 74 species, belonging to 68 genera in total. The number of species of each family well represents the Italian Heteroptera composition, with the prevalence of Miridae and Pentatomidae. The Miridae Criocoris nigripes var. apicalis (Fieber, 1861), a new record in the Alps, and Dicyphus flavoviridis (Tamanini, 1949), an Italian endemic taxon, were collected. Atractotomus parvulus (Reuter, 1878) and Orthotylus viridinervis (Kirschbaum, 1856) were recorded for the first time in Piedmont. Piode is the most Northern area, with Sondrio, where the Mediterranean Lygaeidae Oxycarenus lavaterae (Fabricius, 1784) was found

Egg hatching at different temperatures and relative humidities in Idaea inquinata (Scopoli) (Lepidoptera: Geometridae)

Idaea inquinata (Scopoli) feeds mainly on dried plants, nevertheless, it is also a potential pest of stored products as it is able to develop on cereal products. The few references on the biology of this species do not deal with the influence of temperature and relative humidity on egg hatching. To fill this gap, groups of 100 eggs, 24-48 hours old, were exposed to five constant temperatures (17, 21, 26, 29 and 34±1°C), two relative humidities (35 and 70±5%) and a photoperiod of 0:24 (light:dark); ten tests were carried out. Each test was replicated four times and egg hatching was observed daily. The highest mean number of hatched eggs was observed at 26 and 29±1°C, 70±5% r.h. with 91.5 and 91.0 eggs, respectively. The lowest mean number of hatched eggs was 61.5 observed at 17°C and 70±5% r.h. The mean numbers of hatched eggs, 83.5, 77.5, 78.5 and 79.8 were similar at 21, 26, 29 and 34±1°C, 35±5% r.h., respectively. Eggs hatched between the sixth and the eighth day at all the temperatures tested, except for 17±1°C and 35±5% r.h., where hatching started on the twelfth day. At this temperature, the duration of the hatching period increased with increasing humidity: 11 d at 35% r.h. and 15 d at 70% r.h. Keywords: Egg, Hatching, Temperature, Relative humidity, Rusty wave mot

The effects of competition between larvae of stored-product moths

The competition between Idaea inquinata, Corcyra cephalonica, and Plodia interpunctella on an artificial diet was investigated. The experiments were carried out with eggs laid within 24 hours. In the first experiment, 20 eggs of one species were placed in a ventilated Petri dish with 10 g of diet and 20 eggs of one of the other species; in the second experiment, 20 eggs of one species and, after 7 days, 20 eggs of one of the other species were added. Experiments were carried out at 27\ub11 \ub0C, 70\ub15% R.H. Each experiment was replicated 5 times and the number of days to complete the development and the number of emerged adults were recorded. The number of P. interpunctella adults was not affected by the presence of C. cephalonica or I. inquinata. A delay in the development was only observed when P. interpunctella eggs were added to the medium already colonized by the other species. I. inquinata was the less competitive, as the number of adults decreased and the days to complete the cycle increased. The development of I. inquinata was prevented if P. interpunctella eggs were started at the same time. Larvae of this last species cannibalized eggs of the other two species. I. inquinata was the least competitive due to the longer cycle, the lower mobility and the aggressiveness of the larvae of the other two species that cannibalized its eggs

Light filth method on semolina and pasta

Samples of semolina and pasta were collected from one mill and one pasta plant in Italy for six and four years respectively. They were analyzed by AOAC light filth method (225 g). Altogether, 195 semolina were collected from 2007 to 2012. The mean number of insect fragments detected during this period was 4.9, and each year, a mean of one first instar larva of Stegobium paniceum (L.) was found. A single mite was detected in only one sample. A total of 156 samples of pasta were analyzed during the period 2009 to 2012 and the mean number of fragments in these samples was 10.1. Mandibles of Sitophilus oryzae (L.) and Tribolium spp. were the most identified filths. Fragments were mainly derived from infestation prior to milling, both in semolina and pasta samples. In fact, fragment size was lower than the granulometry of semolina. Rodent hair was found in few samples

Effects of temporary cooling on larvae of Idaea inquinata (Scopoli) (Lepidoptera Geometridae)

Idaea inquinata develops on dried plants with a preference for medicinal plants. The survival of second and fourth instars larvae of I. inquinata exposed to 6 and -18\ub11 \ub0C, for different periods of time, was observed. Groups of 20 larvae were placed at 6\ub11 \ub0C 60\ub15% R.H. for periods of 15, 18, 20 and 25 days and then put in thermostatic chamber at 26\ub11 \ub0C, 70\ub15% R.H. Tests were controlled after 1, 2, 3, 8, 15 and 23 days until adults emergence. The same procedure was used for tests at -18 \ub0C with exposure times of 4, 8 and 24 hours. For all the tested periods at 6\ub11 \ub0C, a mortality higher than 95% was observed in second instar larvae after 1 day at 26 \ub0C. A 100% mortality was observed on the second day at 26\ub0C after treatment at 6 \ub0C for 18, 20, 25, on the third day for 15 days treatment. Few fourth instar larvae, placed for 25 days at 6 \ub0C, were alive after 8 days at 26 \ub0C, but they didn\u2019t emerge as adult; when exposed for 15, 18 and 20 days few individuals developed to adult. Larvae of I. inquinata were susceptible to the treatment at -18 \ub0C. A 100% mortality was observed after 24 hours, when second and fourth instar larvae were treated for 4 hours at -18 \ub0C

The microbiota of Idaea inquinata developing on dry herbs

Idaea inquinata (Scopoli) (Lepidoptera: Geometridae, Idaeini) is a potential pest of stored food, mainly dry herbs. In this study, the role of diet in the shaping of the I. inquinata-associated bacterial community was investigated and its impact on insect performance (i.e., proportion of adult emergence and duration of postembryonic development). Larvae were reared on three diets with different nutritional compositions: (1) Matricaria chamomilla L. flowers, (2) Angelica archangelica L. roots, and (3) artificial diet. A DNA metabarcoding approach targeting V1-V2 and V4 regions of the bacterial 16S rRNA was adopted to characterize the bacterial communities associated with adults and larvae reared on different diets, and estimate their composition and diversity. The core microbiota of this species was found to include some bacterial genera commonly associated with Lepidoptera. When a coverage-based integration of rarefaction and extrapolation of Hill numbers was used to compare groups of samples, the microbial diversity (estimated as phylogenetic diversity) differed among individuals reared on different diets, and also between larvae vs. adults. The lowest taxon diversity was found associated with individuals reared on M. chamomilla. Larvae fed with this fiber-rich diet had also a significantly slower development. The composition of the microbial community varied among individuals with different diets, but not between adults vs. larvae. This study highlights the important role of diet in shaping I. inquinata microbiota, but also suggests that the microbiota of non-feeding adult moths could be partially inherited from larvae

Development of Cadra cautella (Walker), Corcyra cephalonica (Stainton), and Plodia interpunctella (H\ufcbner) (Lepidoptera Pyralidae) on Triticum monococcum L., T. dicoccum Schrank ex Schubler, and T. spelta L.

Groups of 100 eggs (laid 6-24 hours previously) of Cadra cautella, Corcyra cephalonica, and Plodia interpunctella were reared on 30 g of spikelets or kernels of Triticum monococcum, T. dicoccum, and T. spelta in a conditioned room at 26 \ub1 1 \ub0C, 70 \ub1 5 % r.h., and photoperiod 16:8 (L:D). A higher mean number of adults is observed when moths are reared on kernels, except for C. cephalonica on T. monococcum. The mean developmental time is longer with spikelets except when P. interpunctella is reared on T. monococcum. A low number of adults of the three species is observed on spikelets of T. dicoccum and T. spelta. In fact kernels are covered by glumes and inner glumes that hinder larvae feeding. The highest number of adults of C. cautella is observed on kernels of T. dicoccum (76.5 \ub1 7.8). Few adults of this species emerge from spikelets of T. dicoccum (4.7 \ub1 0.5) and T. spelta (4.5 \ub1 1.3). The mean developmental time is not significantly different among kernels (from 49.5 to 54.2 days) and among spikelets (from 61.5 to 66 days) of the different species of cereals. The highest number of C. cephalonica adults is observed on kernels and spikelets of T. monococcum and on kernels of T. dicoccum; numbers are not significantly different (from 78.5 to 79.7 adults). A lower mean number of adults is observed on spikelets of T. dicoccum (28.2 \ub1 1.2) and T. spelta (28.5 \ub1 2) with a longer mean developmental time, 96 \ub1 0.8 and 112.2 \ub1 3.2 days respectively. The shortest mean developmental time is observed on kernels of T. monococcum (54 \ub1 1.8). The highest mean number of adults of P. interpunctella is observed on kernels of T. dicoccum (71 \ub1 5.5) and of T. spelta (70 \ub1 2.2) with mean developmental times of 42 \ub1 0.8 and 36.7 \ub1 0.5 days respectively. Few individuals develop on T. dicoccum (5.2 \ub1 1.3) and T. spelta (2.2 \ub1 1.3) with mean developmental times of 59.2 \ub1 5.4 and 42.5 \ub1 0.6 days

Effect of particle size of soft wheat flour on the development of Ephestia kuehniella Zeller (Lepidoptera : Pyralidae)

The effect of soft wheat flours, characterized by different particle size, protein and starch content, on the development of Ephestia kuehniella was studied. The attractiveness of the Substrata to first and third instar larvae was also considered. The different protein content of the flours did not significantly affect the development of E. kuehniella, nor did it affect the ability of the flours to attract larvae. In tests with soft wheat flours. with the same nutritional value but different particle size, the highest mean number of adults and the shortest developmental period were recorded on samples with greatest particle size (250-419 mu m). In order to test the attractiveness of soft wheat flour to larvae, a one-way olfactometer was used. There were no significant differences observed in the number of first and third instar larvae found on flours with different protein composition and particle size. Larvae of this species show limited mobility, in fact few individuals of either instar can reach the flour from a distance of 2 m. No larvae of either instar contacted the different substrata from a distance of 2.5 m

Temperature-dependent development and survivorship of Idaea inquinata (Scopoli) (Lepidoptera Geometridae) eggs at two humidity levels

Idaea inquinata (Scopoli) mainly feeds on dried plants, nevertheless, it is also a potential pest of stored product as it is able to develop on cereal products. The few references on the biology of this species do not deal with the influence of temperature and relative humidity on egg hatching. To fill this gap, groups of 100 eggs, 24-48 hours old, were exposed to constant temperatures (13, 15, 36, and 38\ub11 \ub0C), two relative humidities (35, 70\ub15%) and a photoperiod of 0:24 (Light:Dark); eight tests were carried out. Each test was replicated four times. The lowest proportion of hatched eggs was observed at 15 \ub0C (9.5) and 36 \ub0C (8.7) with 35\ub15% R.H. while at 13 and 38 \ub0C eggs did not hatch. A non-linear function is used to represent the developmental rates and survivorship of eggs at 35 and 70% R.H. between lower and upper thresholds temperature