Morphological reinforcement,ancient introgressive hybridization and species delimitation in African stem‐borer species of the genus Sesamia Guenée (Lepidoptera: Noctuidae)

Species delimitation, an issue central to systematics and biodiversity studies, is addressed in the epunctifera group of the stem borer genus Sesamia Guenée (Lepidoptera: Noctuidae). This group is composed of four sub‐Saharan species: Sesamia poephaga Tams & Bowden; Sesamia epunctifera Hampson; Sesamia penniseti Tams & Bowden; and Sesamia poebora Tams & Bowden, the taxonomic status of which was unclear. The first species was considered a possible synonym of the second, and the third species was considered a possible synonym of the fourth. An analysis combining morphological, ecological and molecular data enables us to conclude that S. epunctifera and S. poephaga are different species, and that S. poebora is a synonym of S. penniseti. Two new species were discovered: Sesamia firmata sp.n. and Sesamia veronica sp.n. Sesamia firmata sp.n. has atypical genitalic morphology, suggesting a strong selection resulting in a reinforcement of pre‐zygotic isolation. Some specimens previously identified as S. penniseti on the basis of morphology are sisters to S. epunctifera on the mitochondrial tree, and are connected to S. penniseti on the nuclear tree. The mitochondrial distance from S. penniseti and S. epunctifera is 7.6% and 3.9%, respectively, suggesting an ancient mitochondrial introgression from S. epunctifera into S. penniseti. The possible causes of the reinforcement and introgressive hybridization are discussed. This case of mitochondrial introgression, uncommon in Lepidoptera, in which females are the heterogametic sex, may be an exception to Haldane's rule. The hybrid is assigned the rank of species and named Sesamia pennipuncta sp.n.     

Isozymic and metric variation in the Lutzomyia longipalpis complex

Abstract Male Lutzomyia longipalpis of two types from Bolivia were compared using isozyme electrophoresis and wing morphometry. One sample ( ex Chiflonkaka Cave, alt. 2800 m at Toro Toro, Charcas Province, Potosi Department) was 'two-spot' phenotype males (i.e. tergites III and IV with paired pale patches of pheromone glands), whereas two other locality samples (Apa Apa and Imanaco, Sud Yungas Province, La Paz Department) were one-spot male phenotype (only tergite IV with paired pale patches). Multilocus enzyme electrophoresis (using ACON, aGPD, GPI, IDH, MDH, ME, 6PGD, PGM, LAP and PEPB) found no difference between samples from adjacent hen houses at Apa Apa. Nei's standard genetic distance between one-spot samples from Apa Apa and Imanaco (5 km apart, 1500m alt.) was 0.001-0.002, whereas the two-spot males from Toro Toro (800 km away) showed a genetic distance of 0.081 from the one-spot males (Apa Apa and Imanaco). This genetic distance is commensurate with speciation, but may simply be intraspecific differentiation due to 'isolation by distance'.
For comparative wing morphometry, we included additional material of one-spot males from Bolivia (Guyabal, Sud Yungas, La Paz), Brazil, Colombia and Nicaragua. These three other country samples were assumed to be different sibling species in the complex Lutzomyia longipalpis (Lanzaro et al , 1993). Statistics were based on univariate and multivariate analysis. The comparison between size-in and size-free canonical variate analysis (CVA) indicated that the wing morphometric divergence between one-spot and two-spot Bolivian phenotypes was not size dependent and could have taxonomic significance.     

Mineral resources in life cycle impact assessment—part I: a critical review of existing methods

Purpose

The safeguard subject of the Area of Protection “natural Resources,” particularly regarding mineral resources, has long been debated. Consequently, a variety of life cycle impact assessment methods based on different concepts are available. The Life Cycle Initiative, hosted by the UN Environment, established an expert task force on “Mineral Resources” to review existing methods (this article) and provide guidance for application-dependent use of the methods and recommendations for further methodological development (Berger et al. in Int J Life Cycle Assess, 2020).

Methods

Starting in 2017, the task force developed a white paper, which served as its main input to a SETAC Pellston Workshop® in June 2018, in which a sub-group of the task force members developed recommendations for assessing impacts of mineral resource use in LCA. This article, based mainly on the white paper and pre-workshop discussions, presents a thorough review of 27 different life cycle impact assessment methods for mineral resource use in the “natural resources” area of protection. The methods are categorized according to their basic impact mechanisms, described and compared, and assessed against a comprehensive set of criteria.

Results and discussion

Four method categories have been identified and their underlying concepts are described based on existing literature: depletion methods, future efforts methods, thermodynamic accounting methods, and supply risk methods. While we consider depletion and future efforts methods more “traditional” life cycle impact assessment methods, thermodynamic accounting and supply risk methods are rather providing complementary information. Within each method category, differences between methods are discussed in detail, which allows for further sub-categorization and better understanding of what the methods actually assess.

Conclusions

We provide a thorough review of existing life cycle impact assessment methods addressing impacts of mineral resource use, covering a broad overview of basic impact mechanisms to a detailed discussion of method-specific modeling. This supports a better understanding of what the methods actually assess and highlights their strengths and limitations. Building on these insights, Berger et al. (Int J Life Cycle Assess, 2020) provide recommendations for application-dependent use of the methods, along with recommendations for further methodological development.

     

Life cycle of the cereal aphid Sitobion avenae F.: polymorphism and comparison of life history traits associated with sexuality

1. Clones of Sitobion avenae from the west of France exhibited four types of responses in growth chambers to short days and low temperatures: in addition to permanently parthenogenetic clones (anholocyclic) and clones producing both males and parthenogenetic females (androcyclic), lineages producing both mating females and males were categorized into holocyclic and intermediate types, the latter investing into both sexual and parthenogenetic reproduction.
2. Holocyclic, intermediate and androcyclic clones were tested outdoors for sexual production in autumn and results were consistent with those obtained in growth chambers. Eggs from holocyclic and intermediate clone selfings were laid and hatched for most crosses.
3. Reciprocal crosses within and between life cycle variants showed no effect of the type of cross on the number of eggs laid per mating female, their hatching success, or the survival and fecundity of the parthenogenetic females born from eggs (fundatrices).
4. Eggs from intermediate × intermediate crosses hatched 20 days earlier than those involving at least one holocyclic parent. It is suggested that this short diapausing time gives a selective advantage to intermediate clones in oceanic climates, which could compensate for their lower sexual production in autumn.
5. Selfed offspring showed inbreeding depression, which seems to be common in non host-alternating aphids.
6. Mating with androcyclic males affects percentage (lower) and time (longer) of egg hatching, but not the other investigated traits.
7. The significance of intragenotypic strategy mixing in androcyclic and intermediate clones is discussed as an overall adaptation to the uncertainty of winter climate in oceanic zones.