Photoperiod influence on the biology and phenological characteristics of Dichelops melacanthus (Dallas, 1851) (Heteroptera: Pentatomidae)

Abstract

The influence of the photoperiod on the biology and seasonal morphs of Dichelops melacanthus (Dallas, 1851) was studied in the laboratory. Four different photoperiods (11, 12, 13, and 14 hL = hours of light) were tested, keeping the temperature at 25 +/- 1 masculine C and the relative humidity at 65 +/- 5%. Nymph developmental time tended to be longer under shorter photophases (11 and 12 hL). The 14-hour photophase (long day) resulted in lower nymph mortality rates. Females maintained at 13 and 14 hL showed greater weight gain (1st-28th day) than females under 12 hL. D. melacanthus showed reproductive oligopause induced by short photophases, especially when exposed to 11 hL. Under 13 and 14 hL, 85% and 65% of females oviposited, respectively, in comparison to 10% and 15% of females ovipositing under 11 and 12 hL, respectively. Fecundity (number of egg masses and number of eggs/female) was greater in the longer than under the shorter photophases. Seasonal dimorphism induced by photoperiod was observed in D. melacanthus adults. Under short-day conditions (11 and 12 hL), adults showed short and rounded shoulder spines, grayish brown abdomen (mainly in 11 hL), high lipid contents, and lower percentage of mature reproductive organs. Under long-day conditions (13 and 14 hL), the stink bugs showed greatly developed shoulder spines, green abdomen, low lipid contents, and mature reproductive organs.

Nymph developmental time and survivorship, adult longevity, reproduction and body weight of Dichelops melacanthus (Dallas) feeding on natural and artificial diets

“…44 mg), while for males it was comparable to those of bugs fed on natural diets. These results on the natural foods are comparable to those previously reported by Chocorosqui & Panizzi (2003) (ca. 51 and 46 mg, for females and males, respectively).…”

“…On this last food, our data (45%) is very similar to the 44% nymphal mortality reported by Chocorosqui & Panizzi (2002), and identical to the mean mortality obtained for nymphs reared on four different photoperiodic regimes and fed pods (immature) and seeds (mature) of soybean (Chocorosqui & Panizzi 2003). The mortality of nymphs on the artificial diet (60%) was higher than that observed for other species of stink bugs such as Nezara viridula (L.) (28.7-38.4% - Panizzi This result might be due to slight differences in the components of the various artificial diets used by different authors and to the characteristics of D. melacanthus that did not adapt to the diet as well as the other species of stink bugs.…”

Diapause initiation and alterations in the life cycle of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) as induced by photoperiodic conditions

“…The larval stage of non-diapausing G. molesta was longer when neonates (≤ 12h-old) were exposed to photophases of 10, 11, 12, 13, and 14h-long, than under the control (16h), as observed to several other insects (Ali & Ewiess 1977, Mourão & Panizzi 2000, Chocorosqui & Panizzi 2003, Niva & Takeda 2003.…”

Impact of cultivation systems on Dichelops melacanthus (Dallas) (Heteroptera: Pentatomidae) population and damage and its chemical control on wheat

“…2 In parentheses changes (%) in the wheat yield parameters in the no chemical control plots were based on differences compared to the chemical control plots. enters in a state of arrestant development (diapause) underneath debris when the crops are not in the field (Chocorosqui & Panizzi 2003), and is favored in areas undisturbed such as the areas under no-tillage cultivation. Another pentatomid pest of soybean, Euschistus heros (Fabricius), also enters into diapause on the soil underneath fallen dead leaves, after the crop is harvested (Panizzi & Vivan 1997).…”