EJE - Ivo Hodek special issue
Life and work of Ivo Hodek
Oldøich NEDVĖD, Alois HONĖK
Eur. J. Entomol. 120: 157-160, 2023 | DOI: 10.14411/eje.2023.020 
Ivo Hodek, who was well-known for his professional work on ladybirds (Coccinellidae) and insect ecophysiology, as well as a teacher or mentor of many entomologists, and the longest serving editor of the European Journal of Entomology died on June 11, 2021, shortly after his ninetieth birthday. Because of his important contribution to the development of European Journal of Entomology, the editorial board decided to dedicate a special virtual issue of the journal to his memory.
Termination of diapause in the lime seed bug Oxycarenus lavaterae (Heteroptera: Lygaeoidea: Oxycarenidae)
Oldøich NEDVĖD, Plamen KALUSHKOV, Ivo HODEK
Eur. J. Entomol. 120: 150-156, 2023 | DOI: 10.14411/eje.2023.019
The true bug Oxycarenus lavaterae has spread northwards through Europe from the Mediterranean at the beginning of the 21st century. Temperature and photoperiod in particular countries are important for the prediction of further spread. The timing and conditions for the termination of winter diapause in Bulgarian and Czech populations of O. lavaterae were determined. The progress in diapause development in the Bulgarian population was monitored by changes in the duration of the pre-oviposition period under long day (18L : 6D) conditions, which decreased gradually from October to June from 98 to 10 days at 20°C and 62 to 9 days at 25°C....
Stage-specific vulnerability of Harmonia axyridis (Coleoptera: Coccinellidae) to intraguild predation
Geneviève LABRIE, Roberto MESEGUER, Eric LUCAS
Eur. J. Entomol. 120: 70-80, 2023 | DOI: 10.14411/eje.2023.010
The multicoloured Asian ladybeetle, Harmonia axyridis (Pallas), is a widespread invasive ladybird. It is considered a top predator among the aphidophagous coccinellids in North America and Europe; thus, it is supposed to be free from predation pressure by other members of the guild. Our study aims to evaluate the stage-specific vulnerability of H. axyridis to intraguild predation (IGP) by the indigenous Coleomegilla maculata lengi Timberlake and the invasive Propylea quatuordecimpunctata Linnaeus. We hypothesised that (1) H. axyridis stages will be less susceptible to IGP than the two other species, (2) vulnerability...
Distribution, host range and host preferences of Dinocampus coccinellae (Hymenoptera: Braconidae): A worldwide database
Piotr CERYNGIER, Kamila W. FRANZ, Jerzy ROMANOWSKI
Eur. J. Entomol. 120: 26-34, 2023 | DOI: 10.14411/eje.2023.004
Dinocampus coccinellae (Schrank) is a braconid parasitoid of ladybird beetles (Coleoptera: Coccinellidae) and has exceptionally wide geographical and host ranges. Based on published and unpublished sources Dinocampus coccinellae probably occurs throughout the temperate, subtropical and tropical climatic zones, but some regions, such as sub-Saharan Africa (except its southernmost part) and the Malay Archipelago, have not so far been surveyed for this wasp. In most of its extensive range D. coccinellae was present before the widespread use of classical biological control. It is likely, however, to have reached some oceanic islands...
North vs. South: Contrasting patterns in the phenotypic plasticity of the firebug Pyrrhocoris apterus (Hemiptera: Pyrrhocoridae) at the latitudinal extremes of its distribution range
Dmitry KUTCHEROV, Elena B. LOPATINA
Eur. J. Entomol. 119: 454-465, 2022 | DOI: 10.14411/eje.2022.048
In widely distributed insects, some life-history traits are conserved across the whole distribution range and are considered species-specific while other such traits differ geographically. This interplay of geographic variation and phenotypic conservatism is poorly understood even in relatively well-studied model species. Furthermore, a careful study may reveal that conventionally stable traits, such as the lower temperature threshold for development and the sum of degree-days, are both geographically variable and environmentally plastic. We studied how photoperiodic conditions and temperature jointly affect immature development, adult body size and...
Diet and chemical defence in ladybird beetles (Coleoptera: Coccinellidae)
John J. SLOGGETT
Eur. J. Entomol. 119: 362-367, 2022 | DOI: 10.14411/eje.2022.037
In this paper, I review the effects of the diet of ladybirds on chemical defence in this group of beetles. The tendency to reflex bleed and the diversity of autogenously produced alkaloids in different taxa may be evolutionarily related to diet and the likelihood of food limitation. Within predatory species, both prey quantity and quality have been shown to affect autogenous alkaloid production. A few ladybird predators have been suggested to adaptively sequester toxins from their prey for their own defence. However, in most cases the evidence for this is limited, with questions remaining about the costs of accumulated toxins and their defensive value,...
Seasonal and geographical adaptations in the parthenogenetic stick insect, Ramulus mikado (Phasmatodea: Phasmatidae)
Keiji NAKAMURA, Yuuki FUKUSHIMA
Eur. J. Entomol. 119: 354-361, 2022 | DOI: 10.14411/eje.2022.036
Seasonal and geographical adaptations in terms of obligatory embryonic diapause in the parthenogenetic stick insect, Ramulus mikado, were studied. First and second instar nymphs were collected at locations at three latitudes in Japan and reared in the laboratory under a photoperiod of 16L : 8D or 12L : 12D at 25°C. Their eggs were kept at 30°C for 30 or 60 days after oviposition, but no eggs hatched. Hatching was observed more than 100 days after transfer from 30°C to 15°C. The long period between transfer and hatching indicate that eggs in an early embryonic stage of development enter diapause at high-temperatures. The time from oviposition...
Temporal and climatic variation in the colour forms of Adalia bipunctata and Harmonia axyridis (Coleoptera: Coccinellidae) populations in the United Kingdom
Ayman ASIRI, Chris FOSTER
Eur. J. Entomol. 119: 250-259, 2022 | DOI: 10.14411/eje.2022.027
Colour form polymorphism in Adalia bipunctata (Linnaeus, 1785) and Harmonia axyridis (Pallas, 1773) has been extensively studied in the past. Climate, season, and region are known to influence the colour form frequencies of these species, however, this effect is region specific, and the response of populations has changed over time. Here, 5862 photographic records from the UK Ladybird Survey from 2013-2017 were used to assess the geographic variation in colour form frequency (melanic versus non-melanic) of A. bipunctata and H. axyridis across the United Kingdom (UK) in relation to climate and season. Climate data from the...
Diapause among the flesh flies (Diptera: Sarcophagidae)
David L. DENLINGER
Eur. J. Entomol. 119: 170-182, 2022 | DOI: 10.14411/eje.2022.019
The rich diversity of information focusing on pupal diapause in the sarcophagids makes this fly family among the best-understood diapause models. This review summarizes the occurrence of pupal diapause in flesh flies from broad geographic regions of the world, as well as the apparent absence of diapause in select regions. The environmental cues used for programming diapause are discussed, as well as the requirements for breaking diapause. This taxon has been used for experiments ranging from the ecological to the molecular and offers a comprehensive overview of the diapause phenotype. A wide range of diapause attributes define the diapause phenotype...
Photoperiodic induction of adult reproductive diapause in the ladybird beetle Cycloneda munda (Coleoptera: Coccinellidae)
John J. OBRYCKI
Eur. J. Entomol. 119: 148-151, 2022 | DOI: 10.14411/eje.2022.016
The developmental response and the induction and duration of adult hibernal diapause in a North American population of Cycloneda munda (Say) (collected at 38°N, 84.5°W) was determined by rearing individuals at four photoperiods (L:D 16:8, 14:10, 12:12, and 10:14) at 22°C. Preimaginal development of C. munda individuals was slower at L:D 10:14 than at three longer photoperiods. No C. munda females reared at L:D 16:8 entered diapause, 5% of females at L:D 14:10 were in diapause, whereas shorter photoperiods (L:D 12:12 and 10:14) induced diapause in 84% and 100% of females. Cycloneda munda females demonstrated a long-day response...
Provision of small sterile eggs is a circumstance-dependent maternal investment in sibling cannibalism in the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)
Naoya OSAWA
Eur. J. Entomol. 119: 133-139, 2022 | DOI: 10.14411/eje.2022.014
Many aphidophagous ladybird beetles lay clusters of eggs and sibling cannibalism occurs at hatching. Larvae that hatch early tend to cannibalize undeveloped eggs and those that hatch late. The cannibalized eggs, especially those that are sterile, represent a maternal investment in the cannibal and are regarded as "trophic" eggs, which increase their chances of surviving. The characteristics of cannibalized eggs, however, are poorly studied. In this study, I determined the sizes of eggs that developing and undeveloped eggs within egg clusters of Harmonia axyridis (Coleoptera: Coccinellidae). Developing eggs were significantly larger (on average...
Time measurement in insect photoperiodism: The role of photophase duration and light intensity
David SAUNDERS
Eur. J. Entomol. 119: 69-76, 2022 | DOI: 10.14411/eje.2022.007
The initial stages of diapause induction - as summer gives way to autumn - involve a process of time measurement in which the duration of daylength (or nightlength) is determined by a photoperiodic 'clock' based upon the circadian system. In many insects so far examined, a photophase of sufficient duration and illuminance resets a photoperiodic oscillator to a constant phase equivalent to the beginning of the 'subjective night' (Circadian time, CT 12 h) whereupon it proceeds to measure nightlength in a clock of the external coincidence type. A possible exception may be found in the linden bug, Pyrrhocoris apterus, which - in laboratory studies...
Cold and freezing injury in insects: An overview of molecular mechanisms
Jan ROZSYPAL
Eur. J. Entomol. 119: 43-57, 2022 | DOI: 10.14411/eje.2022.005
The present review discusses the molecular mechanisms of injury caused by low temperatures and/or freezing. The review is intended mainly for insect environmental physiologists who focus on the effects of low temperatures. The review successively discusses (1) the effects of low temperatures on the structure and function of macromolecules; (2) the effects of freezing on cells and macromolecules and (3) the mechanisms of damage during thawing and post-thaw. The review shows that injury primarily occurs at the molecular level in terms of damage to proteins, nucleic acids and biological membranes. The damage to macromolecular structures occurs as a result...
The circadian clock gene (Clock) regulates photoperiodic time measurement and its downstream process determining maternal induction of embryonic diapause in a cricket
Shin G. GOTO, Masatoshi NAGATA
Eur. J. Entomol. 119: 12-22, 2022 | DOI: 10.14411/eje.2022.002
In response to short days in autumn, most temperate multivoltine insects enter diapause, a state in which development or reproduction is suppressed or arrested, which serves to coordinate their development and physiology (or that of offspring) with annual changes in the environment (i.e. photoperiodism). This response is mediated by a measurement of time based on photoperiod (photoperiodic time measurement), which is thought to be regulated by a circadian clock. However, some studies also demonstrate the involvement of the circadian clock in an output process that generates phenotypes associated with diapause. To gain further insight into this, we...