A thorough database of research investigating the effects of high-temperature stress on insects is essential for conducting a bibliometric analysis. Currently, the only database that contains comprehensive details on cited references is the Web of Science Core Collection (WoSCC https://webofscience.clarivate.cn/wos/), which is extensively utilized in numerous bibliometric analyses (27–29). Therefore, we used the WoSCC to construct a bibliographic database on the topic of insect responses to high temperatures. Specifically, search strategy: (1) Topic = [(“heat stress” OR “high temperatures” OR “thermal stress” OR “heat conditions” OR “heat waves” OR “heat shock”) AND (“insect” OR “Diptera” OR “Coleoptera” OR “Hemiptera” OR “Lepidoptera” OR “Hymenoptera” OR “Blattodea” OR “Isoptera”)] (These insect orders based on their diversity, ecological, and economic importance). (2) Language = “English”. (3) Article type = (“article” OR “review”). (4) Time = January 1, 1996 to September 2, 2024. After manually filtering the search results to remove irrelevant articles, we obtained a total of 4,417 articles that met the search criteria for bibliometric analysis. Finally, all articles were exported in the form of full records, including cited references, and the exported records were saved as plain text files.

The bibliometric analysis tool utilized in this research aligns with the one applied in earlier studies (29, 30). VOSviewer (version 1.6.20) was used for network visualization (31), CiteSpace (version 6.3.R1 64-bit) for detecting citation bursts and temporal patterns (32, 33), and Bibliometrix R package (Version 4.0.0) for statistical analysis (34, 35).

The Bibliometrix R-package offered a range of innovative and distinctive tools for quantitative investigation within the fields of bibliometrics and scientometrics (34). These tools could be utilized to perform various bibliometric analyses, such as those pertaining to publication metrics, scientific output, citation references, generation of word clouds, and analysis of trending topics (29). VOSviewer was a software program developed by researchers at Leiden University in the Netherlands for the analysis of literature and the visual representation of knowledge (31). The software was open source and enabled the user to examine the intricacies of research problems efficiently through the utilization of a range of features, including clustering, labelling, and density views (30). In this study, CiteSpace and Bibliometrics were used to calculate the total number of publications and annual publications, mean total citations per paper, mean total citations per year, single country publications (SCP), multiple country publications (MCP), H-index, total local cited references, and total citation score of local global. We computed centrality and sigma values. Centrality values indicate a node’s importance and influence in a network, while sigma values reflect the strength of connections between nodes. These values were employed to evaluate influential journals, authors, countries, and academic institutions, as previously described (28, 30). The CiteSpace and VOSviewer software and the Bibliometrix package were employed for the analysis and visualization of the co-citation network of author, country and institution, in addition to the co-occurrence network of keywords. The bar charts of publication counts were generated by Graphpad Prism (Graphpad Prism 9.3.0, Graphpad Software, USA). Furthermore, bibliographic coupling networks were constructed using the Bibliometrix package. Bibliographic Coupling Network: A network where nodes represent documents, and links indicate shared references, showing how documents are related through common citations.

Over the 30 years from 1996 to 2024, a total of 4417 articles have been published in the field of insect responses to high−temperatures. Figure 1A shows a marked increase in publications after 2012, while the number of publications fluctuated, it overall maintained a steady growth trend, with an average annual increase of 3.59%, indicating growing research attention. For the citations of papers, both the total number of citations per article and the average citations per year have decreased, this could be due to shorter accumulation time rather than reduced interest ( Figures 1B, C ). The peak mean value of global total citations occurred in 2013, reaching 46.21 times, while the lowest was recorded in 2023 at only 3.40 times ( Figure 1B ). The highest mean total citations were also noted in 2013 (3.85 times) and 2020 (3.61 times), whereas the lowest average total citation was just 1.70 times in 2023 ( Figure 1C ). Data for 2024 is not included as the year is not yet complete.

This multidisciplinary literature dataset spans across multiple disciplinary fields, including Zoology (3,051), Environmental Sciences Ecology (2,856), and Biochemistry Molecular Biology (2,775). A total of 847 different sources were identified in the literature, with the ten most frequently publications presented in Figure 2A . The top-ranking journal was PLoS One, which published 208 articles with 6,397 citations. While Scientific Reports, Journal of Thermal Biology and Insects with 125, 108 and 104 articles with 2,508, 2,223, and 801 citations published followed closely behind, respectively ( Figure 2A , Supplementary Table S1 ). The PLoS One journal also ranks first, with an H-index and a G-index of 41 and 61, respectively ( Supplementary Table S1 ). However, Proceedings of the National Academy of Sciences (PNAS) is the most cited journal (7,187 citations) with 33 articles and a g-index of 26. These results demonstrate that the journal of PLoS One is an important journal in the field and that PNAS is becoming increasingly important.

To gain a deeper understanding of the phenomenon of authorship and collaboration in the field, an analysis was conducted on three key factors: country, institution, and author. As shown in Figure 2B , our analysis shows that China and the USA are the two countries with the largest number of scientific publications, with 1,129 and 796 articles, respectively, corresponding to a cumulative share of 43.6%. Nevertheless, neither country is in the highest position concerning the average article citation index, with China having a relatively low score of 14.6 ( Supplementary Table S2 ). For the proportion of Multiple country publications (MCP), our analysis shows that all publications have an overall MCP below 20%. Specifically, the two countries with the highest output of scientific research, namely China and the USA, exhibited MCP ratios below the average, at 18.5% and 23.2%, respectively ( Figure 2B , Supplementary Table S2 ). In contrast, the countries with a relatively limited number of articles, namely the United Kingdom, Belgium, South Africa, France and Denmark, exhibit higher MCP rates, with 55.2%, 51.6%, 50.0%, 47.1%, and 42.6%, respectively ( Figure 2B , Supplementary Table S2 ). The percentage of MCP that a country contributed is indicative of the degree of international collaboration in the country, our research findings suggest that there is potential for enhancement in international collaboration within the field. The framework of national collaborations is illustrated in Figure 2C , which depicts China, the USA, India, Brazil, and Germany as the primary actors within this network. Analyses of research institutions reveal similar trends to countries, with five of the top 10 institutions coming from China, two from the USA, and one each from France, Denmark, and Russia ( Supplementary Table S3 ).

Chinese Academy of Agricultural Sciences ranked first with 200 articles contributed with had a low centrality score of 0.05 ( Supplementary Table S3 ). Except for the University of California system, which published 195 articles with a centrality value of 0.33, the centrality of the rest of the institutions was low ( Supplementary Table S3 ). The higher the centrality, the more central and influential the institution is in the cooperation network; the lower it is, the more marginal and less influential the institution is. This suggests that the current connections among institutions are not tight enough, the collaboration between the various institutions needs to be deepened. Institutions should engage in more collaboration, including inter-institutional and international partnerships. The cooperation network of relevant institutions is shown in Figure 3A , with the Chinese Academy of Agricultural Sciences, the University of California, and the National Center for Scientific Research (CNRS) as significant positions.

We included a total of 299 authors and established a collaborative network, as shown in Figure 3B that authors from the same research institution show stronger collaborative relationships. The ten authors with the highest productivity and greatest influence in the field of insect responses to high temperatures are presented in Supplementary Table S3 . Du YZ and Hoffmann AA. are considered the most influential authors in the field of insect responses to high temperatures, having published 46 and 43 research papers on the topic, respectively. Additionally, Hoffmann AA. is the top-ranked author globally in terms of h-index, g-index, and total citations ( Figure 3B , Supplementary Table S3 ). Also, to provide a more intuitive representation of the affiliations and countries to which authors belong, Sankey diagrams are employed to visualize the relationships between authors, affiliations and countries ( Supplementary Figure S1 ).

To achieve a more comprehensive understanding of the influential authors, journals, and references within the field, a co-citation analysis was performed, as illustrated in Figure 4 . The visual network of co-cited authors is presented in Figure 4A . The author with the highest number of citations is Hoffmann, AA, with 1,009 citations, followed by Sorensen, JG, Colinet, H, Chown, SL, and Sinclair, BJ, with 687, 626, 487, and 427 citations, respectively ( Figure 4A , Supplementary Table S4 ), indicating their relative popularity. Additionally, we found that there is no significant correlation between centrality and co-citation counts, indicating that the indication of international influence may not be directly proportional to the strength of a partnership. Figure 4B and Supplementary Table S5 showed cited journals and frequency counts, PNAS (7,187 citations) was the top-ranked journal, followed by PLoS One (6,403 citations), Journal of Insect Physiology (6,177 citations), Nature (4,595 citations), and Science (4,621 citations). In addition, 700 references (the minimum number of which was 20) were collated from 4,417 publications to analyze the co-cited references ( Figure 4C ). Among them, the most-cited reference was published by Feder M.E., et al. (395 citations); this publication demonstrated the essential function of Heat Shock Proteins in the response of organisms to stress (36) ( Figure 4C , Supplementary Table S6 ). The second reference was published by Hoffmann, A.A., and has been cited 223 times ( Figure 4C , Supplementary Table S6 ), this study reports how Drosophila research has been used to understand the evolution of plastic responses, trade-offs, and limits to selection. It also establishes connections between laboratory research and the evolutionary mechanisms that give rise to population and species differences (37). In brief, the most frequently cited works tend to be the most actively discussed in the context of citation bursts.

According to the theoretical framework of research fronts, the research fronts in a certain field represent all documents published within a certain period of time (33). The emergence of salient topics is discerned through an examination of keywords across all published documents (29).

To explore the hot topics in this field, we used the Bibliometrix tool to conduct keyword analyses, including word cloud visualization ( Figure 5A ), co-occurrence analysis ( Figure 5B ), and thematic evolution analysis ( Figure 5C ). As shown in Figure 5A and Supplementary Figure S2 , the 10 most frequent keywords consisted of expression, temperature, heat-shock proteins, climate change, gene expression, drosophila-melanogaster, stress, responses, drosophila, and tolerance. By performing keyword co-occurrence analysis, keywords can be categorized into three groups, as shown in Figure 5B . The red cluster represents the adaptation mechanisms and physiological responses of insects under heat-stress conditions. Expression, temperature, responses, tolerance, etc. are the most common keywords, oxidative stress, growth, adaptation, performance and life-span are also frequently mentioned ( Figure 5B , Supplementary Table S7 ). The cluster explains how insects adapt to and cope with heat stress through mechanisms involving gene expression and protein regulation, including aspects such as oxidative stress, tolerance, metabolic adjustments, growth, and lifespan. The primary keywords of the blue cluster are heat-shock proteins, climate change, evolution, phenotypic plasticity, thermal tolerance, and acclimation ( Figure 5B , Supplementary Table S7 ). These keywords collectively focus on how insects adapt to climate change and heat stress conditions through heat-shock proteins and evolutionary mechanisms, covering aspects such as phenotypic plasticity, population adaptation, body size changes, reproduction, and population structure. The green cluster includes the terms gene expression, drosophila-melanogaster, resistance, identification, heat-shock, evolutionary, hsp70, heat-shock-protein, molecular chaperones, and thermal stress ( Figure 5B , Supplementary Table S7 ). These keywords collectively point to research on the expression and tolerance mechanisms of heat shock proteins (especially HSP70) in Drosophila and other Diptera insects under heat stress conditions, including aspects such as the upregulation of gene expression, the role of molecular chaperones, and the impact of heat stress on survival. As illustrated in Figure 5C , the trending topics also align with the findings of the keyword co-occurrence analysis. The most frequent keywords in different years include virulence, gene expression, heat stress, heat shock protein, and hsp70. This result indicates that heat shock proteins play a crucial role in insect response to high temperatures, and HSP70 is one of the most important members among them. Interestingly, since 2018, the term “climate change” has begun to appear and continues to be present ( Figure 5B ). This indicates that researchers are directing their attention towards the impact of climate change on the capacity of insects to adapt to elevated temperatures, as well as the physiological and biological alterations they undergo in response to global warming. This suggests that researchers are increasingly focusing on the effects of climate change on the ability of insects to adapt to elevated temperatures, as well as the physiological and biological changes they undergo in response to global warming. It is also interesting that the word “drought” appears suggesting that researchers are potentially also addressing other environmental factors such as precipitation and humidity. Connected with this, changes in soil temperature and humidity, as well as air quality such as ozone concentrations, occurring in conjunction with high temperatures, continue to require more research. Furthermore, this signifies an increasing acknowledgement of the significance of comprehending the mechanisms through which insects, as integral components of ecosystems, adapt and maintain their survival in the face of global climate change.

In order to gain insight into research frontiers in this field, we analyzed the Sigma values of literature pertaining to insect response to high temperatures (including corresponding references) and summarized the top 10 articles with the highest Sigma values ( Table 1 ). The article with the highest sigma value is that of Overgaard (2012), published in the open-access journal PLOS ONE (38) ( Table 1 ). The second one is Terblanche JS (2011) which was published in the journal ‘Experimental Biology’ (39) ( Table 1 ). It is noteworthy that in 2016, the paper ‘What can plasticity contribute to insect responses to climate change?’ (40) was published. The 2015 paper ‘Stage-specific heat effects: timing and duration of heat waves alter demographic rates of a global insect pest.’ (41) and the 2014 paper ‘Strong negative effects of simulated heat waves in a tropical butterfly.’ (42) ( Table 1 ). Despite their published relatively late, these papers have achieved high Sigma values, indicating that the emergence of disasters such as climate change and heat waves has attracted significant attention within the scientific community. Furthermore, the research presented in these papers reflects the current research frontier and hotspot in this field, namely the urgent need for insects to respond to climate change and heat waves.

Furthermore, to explore the research evolution in the field of insect responses to high temperatures, we undertook a citation bibliographic coupling analysis of the most frequently cited references. A complex bibliographic coupling network of references was constructed by using CiteSpace software, as illustrated in Figure 6 , identifying fifteen clusters across all references, thus offering a perspective that extends beyond the mere occurrence of keywords. The largest cluster is the #0 green peach aphid, with an S value of 0.949. The article by Chen et al. (2022), represents the key reference within this cluster ( Figure 6 , Table 2 ), which suggests that it has a relatively high impact or potential influence within the context of the “green peach aphid” cluster. In addition to the #0 green peach aphid, a clustering group of #2 Drosophila ananassae, #5 Honey bee, #6 Brown planthopper, and #10 Copper butterflies were also discovered ( Figure 6 , Table 2 ). These insects serve as crucial models for research in genetics and evolutionary biology, social behavior and neurobiology, agricultural pest resistance and ecology, as well as evolutionary biology and ecology (48–50). Among these cluster, #6 Brown planthopper has a high frequency of 140, which is likely because it is a hotspot for agricultural pests and its study has received much attention. Researchers in multiple fields are committed to delving deeper into the biology and behavioral mechanisms of brown planthopper in order to better address the challenges of this agricultural pest. #10 copper butterflies have a frequency of 115, indicating strong research interest in their ecological roles and conservation. With respect to the study of insect responses to high temperatures, chronologically research attention has shifted from an emphasis on #8 comparing phenotypic effect toward an investigation of #7 key trait, #3 metabolomic basis and #4 female fertility ( Figure 6 , Table 2 ), a transition marks a shift in focus from the description of macroscopic characteristics to an exploration of the biochemical and reproductive mechanisms occurring at the micro-level, aiming to uncover biological responses and adaptive strategies under heat stress. Interestingly, the clustering of #1 insecticide exposure was also observed ( Figure 6 , Table 2 ), which may suggest a potential synergistic effect or interaction between high-temperature exposure and insecticide exposure, or possibly a shared response mechanism. This discovery not only reveals the multiple environmental pressures faced by insects but also suggests that in the context of climate warming, we may need to reassess and adjust insecticide use strategies and dosages.